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  • 1.
    Areitioaurtena, M.
    et al.
    Ikerlan Technology Research Centre, Basque Research and Technology Alliance (BRTA), Arrasate-Mondragon, Spain.
    Segurajauregi, U.
    Ikerlan Technology Research Centre, Basque Research and Technology Alliance (BRTA), Arrasate-Mondragon, Spain.
    Akujärvi, V.
    Division of Production and Materials Engineering, Lund University, Lund, Sweden.
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Division of Solid Mechanics, Lund University, Lund, Sweden.
    Urresti, I.
    Ikerlan Technology Research Centre, Basque Research and Technology Alliance (BRTA), Arrasate-Mondragon, Spain.
    Ukar, E.
    Department of Mechanical Engineering, University of the Basque Country, Bilbao, Spain.
    A semi-analytical coupled simulation approach for induction heating2021In: Advanced Modeling and Simulation in Engineering Sciences, ISSN 2213-7467, Vol. 8, no 1, article id 14Article in journal (Refereed)
    Abstract [en]

    The numerical simulation of the induction heating process can be computationally expensive, especially if ferromagnetic materials are studied. There are several analytical models that describe the electromagnetic phenomena. However, these are very limited by the geometry of the coil and the workpiece. Thus, the usual method for computing more complex systems is to use the finite element method to solve the set of equations in the multiphysical system, but this easily becomes very time consuming. This paper deals with the problem of solving a coupled electromagnetic - thermal problem with higher computational efficiency. For this purpose, a semi-analytical modeling strategy is proposed, that is based on an initial finite element computation, followed by the use of analytical electromagnetic equations to solve the coupled electromagnetic-thermal problem. The usage of the simplified model is restricted to simple geometrical features such as flat or curved surfaces with great curvature to skin depth ratio. Numerical and experimental validation of the model show an average error between 0.9% and 4.1% in the prediction of the temperature evolution, reaching a greater accuracy than other analyzed commercial softwares. A 3D case of a double-row large size ball bearing is also presented, fully validating the proposed approach in terms of computational time and accuracy for complex industrial cases.

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  • 2.
    Areitioaurtena, Maialen
    et al.
    Basque Res & Technol Alliance BRTA, Ikerlan Technol Res Ctr, Paseo JM Arizmendiarrieta 2, Arrasate Mondragon 20500, Spain..
    Segurajauregi, Unai
    Basque Res & Technol Alliance BRTA, Ikerlan Technol Res Ctr, Paseo JM Arizmendiarrieta 2, Arrasate Mondragon 20500, Spain..
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Lund Univ, Div Solid Mech, POB 118, SE-22100 Lund, Sweden..
    Cabello, Mario J.
    Basque Res & Technol Alliance BRTA, Ikerlan Technol Res Ctr, Paseo JM Arizmendiarrieta 2, Arrasate Mondragon 20500, Spain..
    Ukar, Eneko
    Univ Basque Country UPV EHU, Fac Engn Bilbao, Dept Mech Engn, Plaza Torres Quevedo 1, Bilbao 48013, Spain..
    Influence of induction hardening residual stresses on rolling contact fatigue lifetime2022In: International Journal of Fatigue, ISSN 0142-1123, E-ISSN 1879-3452, Vol. 159, article id 106781Article in journal (Refereed)
    Abstract [en]

    Rolling contact fatigue is a unique mode of fatigue that components under cyclic contact loading experience. In this work, the impact of induction hardening residual stresses in rolling contact fatigue lifetime is investigated experimentally and numerically using the Dang Van multiaxial criterion. Various residual stress fields from induction hardening are simulated using the finite element method and are mapped into a classical monocontact finite element model. The impact of induction hardened residual stresses on the lifetime of a component has been investigated, and the importance of incorporating the residual stress profile into fatigue life assessments is affirmed.

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  • 3.
    Areitioaurtena, Maialen
    et al.
    Basque Res & Technol Alliance BRTA, Ikerlan Technol Res Ctr, Paseo JM Arizmendiarrieta 2, Arrasate Mondragon 20500, Spain..
    Segurajauregi, Unai
    Basque Res & Technol Alliance BRTA, Ikerlan Technol Res Ctr, Paseo JM Arizmendiarrieta 2, Arrasate Mondragon 20500, Spain..
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Lund Univ, Div Solid Mech, POB 118, S-22100 Lund, Sweden..
    Cabello, Mario J.
    Basque Res & Technol Alliance BRTA, Ikerlan Technol Res Ctr, Paseo JM Arizmendiarrieta 2, Arrasate Mondragon 20500, Spain..
    Ukar, Eneko
    Univ Basque Country, Dept Mech Engn, Alameda Urquijo S-N, Bilbao 48013, Spain..
    Numerical and experimental investigation of residual stresses during the induction hardening of 42CrMo4 steel2022In: European journal of mechanics. A, Solids, ISSN 0997-7538, E-ISSN 1873-7285, Vol. 96, article id 104766Article in journal (Refereed)
    Abstract [en]

    The usage of induction hardening in the industry has increased in the last years due to its efficiency and repeatability. Induction hardening produces a hard martensitic layer on the specimen surface, which is accompanied by the generation of compressive residual stresses in the hardened case and tensile stresses in the untreated core. Residual stresses generated by induction hardening greatly impact on fatigue performance, as they act as crack growth retardants. In this work, a multiphysical coupled finite element model is developed to simulate induction hardening and compute the final residual stress state of the specimens along the microstructural transformations and hardness evolution. The impact of the transformation induced plasticity strain in the stress-state of the specimen during the process is also studied. The experimental validation shows that considering the transformation induced plasticity in induction hardening simulations improves the residual stress predictions, concluding that this effect should be included to achieve good residual stress predictions, especially in the subsurface region.

  • 4.
    Areitioaurtena, Maialen
    et al.
    Ikerlan Technology Research Centre, Basque Research and Technology Alliance (BRTA). Paseo J.M. Arizmendiarrieta 2, 20500 Arrasate-Mondragon, Spain.
    Segurajauregi, Unai
    Ikerlan Technology Research Centre, Basque Research and Technology Alliance (BRTA). Paseo J.M. Arizmendiarrieta 2, 20500 Arrasate-Mondragon, Spain.
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Division of Solid Mechanics, Lund University, P.O. Box 118, SE-221 00 Lund, Sweden.
    Cabello, Mario J.
    Ikerlan Technology Research Centre, Basque Research and Technology Alliance (BRTA). Paseo J.M. Arizmendiarrieta 2, 20500 Arrasate-Mondragon, Spain.
    Ukar, Eneko
    Department of Mechanical Engineering, University of the Basque Country, Alameda Urquijo s/n, 48013 Bilbao, Spain.
    Numerical and experimental investigation on the residual stresses generated by scanning induction hardening2022In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 108, p. 827-832Article in journal (Refereed)
    Abstract [en]

    Induction hardening is widely used in the industry as a surface heat treatment that improves the surface and the subsurface hardness of components greatly. The hardened case, which usually is a few mm, highly impacts the surface and structural integrity of the component. In this work, we simulate the scanning induction hardening process by means of finite element modeling. The computed hardness, microstructure, and residual stress profile are compared with experimentally measured data using several surface and subsurface characterization techniques. A very good agreement is found between the simulated and experimentally measured residual stresses, which were characterized by the incremental hole drilling technique.

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  • 5.
    Areitioaurtena, Maialen
    et al.
    Ikerlan Technology Research Centre, Basque Research and Technology Alliance (BRTA). Paseo J.M. Arizmendiarrieta 2, 20500 Arrasate-Mondragon, Spain.
    Segurajauregi, Unai
    Ikerlan Technology Research Centre, Basque Research and Technology Alliance (BRTA). Paseo J.M. Arizmendiarrieta 2, 20500 Arrasate-Mondragon, Spain.
    Urresti, Iker
    Ikerlan Technology Research Centre, Basque Research and Technology Alliance (BRTA). Paseo J.M. Arizmendiarrieta 2, 20500 Arrasate-Mondragon, Spain.
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Ukar, Eneko
    Department of Mechanical Engineering. University of the Basque Country. Alameda Urquijo s/n, 48013 Bilbao, Spain.
    Predicting the induction hardened case in 42CrMo4 cylinders2020In: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 87, p. 545-550Article in journal (Refereed)
    Abstract [en]

    Induction hardening has the potential to produce favorable surface integrity that can improve fatigue performance and extend the lifetime of a component. The localized superficial heating provided by induction is the main advantage of this process, as it allows the core to remain intact and, therefore, ductile, while the surface is hardened. Achieving favorable characteristics in the hardened case is of great importance, as this process is usually applied to load bearing and wear-susceptible metallic components. The simulation of the hardening process by induction heating is a complex and challenging task at which many efforts have been directed in the last years. Due to the numerous interactions of the many physics that take part in the process (electromagnetic, thermal, microstructural and mechanical), a highly coupled finite element model is required for its numerical simulation. In this work, a semi-analytical induction heating model is used to compute the induction hardening process, predicting the size and shape of the hardened layer and the distribution of the hardness. Using the semi-analytical model allows the computational time to be much faster compared to a fully coupled model using a commercial software, where the time consumption for the presented 2D case is reduced by 20 %. Experimental validation is presented for cylindrical 42CrMo4 billets heated by a short solenoidal inductor, which shows good agreement with the predicted results, reaching an average error of 3.2 % in temperature estimations.

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  • 6.
    Ehrlin, Niklas
    et al.
    Malmö högskola, Faculty of Technology and Society (TS).
    Bjerkén, Christina
    Malmö högskola, Faculty of Technology and Society (TS).
    Fisk, Martin
    Malmö högskola, Faculty of Technology and Society (TS).
    Cathodic hydrogen charging of Inconel 7182016In: AIMS Materials Science, ISSN 2372-0484, Vol. 3, no 4, p. 1350-1364Article in journal (Refereed)
    Abstract [en]

    The nickel based superalloy IN718 is known to be prone to hydrogen sensitivity, causing degradation of its mechanical properties. Therefore, during mechanical testing of hydrogen charged samples, a well-defined hydrogen distribution is essential to better understand the influence of hydrogen on dislocation movement and plasticity behavior. The possibility of charging cylindrical specimens of IN718 with hydrogen using cathodic charging is investigated. The method is based on an electro-chemical process using a molten salt electrolyte. The resulting hydrogen concentration is measured for various radii, and it is shown that the anisotropic diffusion coefficient resulting from electromigration, inherent in the charging method, must be taken into account as it has a major impact on the charging parameters of IN718. Also, no evidence of degassing during storage is found. Further, changes in surface roughness were examined by SEM, and only limited surface degradation is observed, which is not considered to significantly affect the results.

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  • 7.
    Ehrlin, Niklas
    et al.
    Malmö högskola, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Fisk, Martin
    Malmö högskola, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Bjerkén, Christina
    Malmö högskola, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Flow stress model for hydrogen degraded Inconel 7182017In: ICF 2017 - 14th International Conference on Fracture, Vol 1 / [ed] Emmanuel E. Gdoutos, International Conference on Fracture , 2017, p. 233-234Conference paper (Refereed)
    Abstract [en]

    A mechanism based material model has been developed to simulate hydrogen enhanced localized plasticity for superalloy IN718 in the present work. The model accounts for the increase in mobility of the moving dislocation during plastic deformation, whenever exposed for hydrogen. Two different hydrogen charging methods have been used: cathodic charging with molten salt as electrolyte, and high temperature gas chamber charging. Tensile tests performed at a strain rate of 5×10−5 s-1 show a clear difference between charged samples and uncharged samples. No or small differences could be seen between the two different charging methods. The material model was fitted against the experimental curves using a minimising method alternating fitting parameters. The agreement between the experimental value and the model was good.

  • 8.
    Ehrlin, Niklas
    et al.
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Division of Solid Mechanics, Lund University, P.O. Box 118, SE-221 00 Lund, Sweden.
    Bjerkén, Christina
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Flow stress model for hydrogen degraded Inconel 7182018In: Mechanics of materials, ISSN 0167-6636, E-ISSN 1872-7743, Vol. 119, p. 56-64Article in journal (Refereed)
    Abstract [en]

    For life time estimation, it is desirable to capture the lowering of yield strength and premature failure that some alloys exhibits when subjected to hydrogen. For this, a mechanism based material model has been developed to simulate the hydrogen enhanced localized plasticity (HELP) for the superalloy IN718. The model accounts for the increase in mobility of moving dislocations during plastic deformation, whenever hydrogen is present in the material. Tensile tests performed at four different strain rates: 5 x 10(-5), 5 x 10(-4), 5 x 10(-3) and 5 x 10(-2) s(-1) show a difference in yield behaviour between hydrogen pre-charged and uncharged samples. No strain rate dependency of the hydrogen effect could be concluded. Two different hydrogen charging methods have been used: cathodic charging with molten salt as electrolyte, and high temperature gas charging. No differences in the tensile response could be seen between the two different charging methods. The proposed model was fitted against the experimental curves using a minimizing method and model parameters were obtained. Comprising iteratively updated parameters, the model is suited for implementation in finite element software.

  • 9.
    Ericsson, A.
    et al.
    Division of Solid Mechanics, Lund University, PO Box 118, Lund, SE 22100, Sweden.
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Division of Solid Mechanics, Lund University, PO Box 118, Lund, 22100, SE, Sweden.
    Hallberg, H.
    Division of Solid Mechanics, Lund University, PO Box 118, Lund, SE 22100, Sweden.
    Modeling of nucleation and growth in glass-forming alloys using a combination of classical and phase-field theory2019In: Computational materials science, ISSN 0927-0256, E-ISSN 1879-0801, Vol. 165, p. 167-179Article in journal (Refereed)
    Abstract [en]

    For metallic glasses, it is of vital importance to understand the glass formation properties and to be able to predict the crystallization process in the supercooled liquid. In the present work, we model the process of nucleation and growth using a combination of classical nucleation and phase-field theory. A diffusion coupled phase-field model is used to evaluate the work of formation and the growth behavior of the critical nucleus. The results are combined with classical nucleation and JMAK theory in order to estimate the glass forming ability of the compositions Cu64Zr36, Cu10Zr7 and CuZr2 in terms of TTT-diagrams and critical cooling rates. It is found that the work of formation of the critical nucleus from the phase-field theory agrees with the classical theory when the critical size is larger than the width of the solid-liquid interface. At smaller critical sizes, the work of formation deviates approximately linearly between the two theories. Furthermore, it is shown that the growth behavior from the phase-field simulations agree with analytical expressions of the growth rate from the classical theory.

  • 10.
    Ericsson, A.
    et al.
    Division of Solid Mechanics, Lund University, PO Box 118, Lund, SE 22100, Sweden.
    Pacheco, V.
    Department of Chemistry, Ångström Laboratory, Uppsala University,Box 523, Uppsala, SE 75120, Sweden.
    Marattukalam, J. J.
    Department of Physics & Astronomy, Materials Physics, Uppsala University, Box 516, Uppsala, SE 75121, Sweden.
    Dalgliesh, R. M.
    ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0QX, UK.
    Rennie, A. R.
    Centre for Neutron Scattering, Uppsala University, Box 516, Uppsala, SE 75121, Sweden.
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Division of Solid Mechanics, Lund University, PO Box 118, Lund, SE 22100, Sweden.
    Sahlberg, M.
    Department of Chemistry, Ångström Laboratory, Uppsala University,Box 523, Uppsala, SE 75120, Sweden.
    Crystallization of a Zr-based metallic glass produced by laser powder bed fusion and suction casting2021In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 571, article id 120891Article in journal (Refereed)
    Abstract [en]

    The crystallization behaviour during low temperature annealing of samples of the Zr59.3Cu28.8Al10.4Nb1.5 (at%) bulk metallic glass produced by suction casting and the laser powder bed fusion (LPBF) process were studied with small angle neutron scattering (SANS), X-ray diffraction and scanning electron microscopy. The in-situ SANS measurements during isothermal annealing reveals that the phase separation in the LPBF processed material proceeds at a smaller characteristic length-scale than the cast material. Quantitative analysis of the SANS data shows that, while the crystallization process in both materials proceed through rapid nucleation followed by diffusion limited growth, the LPBF processed material crystallizes with a smaller cluster size and at a higher rate. The smaller cluster size is attributed to the elevated oxygen content in the LPBF processed material which reduces the nucleation barrier and thus the thermal stability.

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  • 11.
    Ericsson, A.
    et al.
    Division of Solid Mechanics, Lund University, PO Box 118, Lund, 22100, SE, Sweden.
    Pacheco, V
    Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, Uppsala, 75120, SE, Sweden.
    Sahlberg, M.
    Department of Chemistry, Ångström Laboratory, Uppsala University, Box 523, Uppsala, 75120, SE, Sweden.
    Lindwall, J.
    Mechanics of Solid Materials, Luleå Technical University, Luleå, 97187, SE, Sweden.
    Hallberg, H.
    Division of Solid Mechanics, Lund University, PO Box 118, Lund, 22100, SE, Sweden.
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Division of Solid Mechanics, Lund University, PO Box 118, Lund, 22100, SE, Sweden.
    Transient nucleation in selective laser melting of Zr-based bulk metallic glass2020In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 195, article id 108958Article in journal (Refereed)
    Abstract [en]

    The crystallization rate during selective laser melting (SLM) of bulk metallic glasses (BMG) is a critical factor in maintaining the material's amorphous structure. To increase the understanding of the interplay between the SLM process and the crystallization behavior of BMGs, a numerical model based on the classical nucleation theory has been developed that accounts for the rapid temperature changes associated with SLM. The model is applied to SLM of a Zr-based BMG and it is shown that the transient effects, accounted for by the model, reduce the nucleation rate by up to 15 orders of magnitude below the steady-state nucleation rate on cooling, resulting in less nuclei during the build process. The capability of the proposed modelling approach is demonstrated by comparing the resulting crystalline volume fraction to experimental findings. The agreement between model predictions and the experimental results clearly suggests that transient nucleation effects must be accounted for when considering the crystallization rate during SLM processing of BMGs. (c) 2020 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

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  • 12.
    Ericsson, Anders
    et al.
    Lund Univ, Div Solid Mech, POB 118, SE-22100 Lund, Sweden..
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Lund Univ, Div Solid Mech, POB 118, SE-22100 Lund, Sweden.;Malmö Univ, Dept Mat Sci & Appl Math, SE-20506 Malmö, Sweden..
    Modeling of Diffusion-Controlled Crystallization Kinetics in Al-Cu-Zr Metallic Glass2022In: Metals, ISSN 2075-4701, Vol. 12, no 5, p. 1-16, article id 867Article in journal (Refereed)
    Abstract [en]

    Crystallization is a major challenge in metallic glass production, and predictive models may aid the development of controlled microstructures. This work describes a modeling strategy of nucleation, growth and the dissolution of crystals in a multicomponent glass-forming system. The numerical model is based on classical nucleation theory in combination with a multicomponent diffusion-controlled growth model that is valid for high supersaturation. The required thermodynamic properties are obtained by coupling the model to a CALPHAD database using the Al-Cu-Zr system as a demonstrator. The crystallization of intermetallic (Al, Cu)(m)Zr-n phases from the under-cooled liquid phase were simulated under isothermal as well as rapid heating and cooling conditions (10(-1)-10(6) Ks(-1)). The obtained time-temperature transformation and continuous-heating/cooling transformation diagrams agree satisfactorily with the experimental data over a wide temperature range, thereby, demonstrating the predictability of the modeling approach. A comparison of the simulation results and experimental data is discussed.

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  • 13.
    Fisk, Martin
    Malmö högskola, School of Technology (TS).
    Induction Heating2014In: Encyclopedia of Thermal Stresses / [ed] Richard B Hetnarski, Springer, 2014, p. 2419-2426Chapter in book (Other academic)
    Abstract [en]

    Induction heating is the process of heating a material through the generation of eddy current. An external applied alternating magnetic field is applied, and heat is generated from the resistance to the eddy current (i.e., Joule heating). Eddy current is the main heat source; however, heat may also be generated in magnetic materials from alternating magnetization and hysteresis. The induced current is commonly called eddy current, although it is also known as Foucault current after its discoverer, Jean Bernard Léon Foucault (1819–1868). We will, in the following text, use the notation eddy current. In general, the eddy current distribution inside the work piece is not uniform. The magnitude of the eddy current attenuates exponentially beneath the surface, which implies that the current density near the surface is greater than at a depth. The surface of a material will therefore be heated faster than the interior. This phenomenon is referred to as the skin effect.

  • 14.
    Fisk, Martin
    et al.
    Malmö högskola, School of Technology (TS).
    Andersson, Joel
    du Rietz, Rickard
    Malmö högskola, School of Technology (TS).
    Haas, Sylvio
    Hall, Stephen
    Precipitate evolution in the early stages of ageing in Inconel 718 investigated using small-angle x-ray scattering2014In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 612, p. 202-207Article in journal (Refereed)
    Abstract [en]

    Microstructural evolution during the early stages of ageing (less than one hour) in a Ni–Cr–Fe based superalloy Inconel 718 (IN718) has been investigated using Small-Angle X-ray Scattering (SAXS). The effects of precipitate kinetics on the precipitate size distribution are compared indirectly with SAXS measurements by using Vickers microhardness data. The microhardness increased after 4 min of ageing at a temperature of 760 °C, although the recorded SAXS data did not reveal the precipitate size distribution. This indicates that the precipitates had not evolved enough to be detected, but still a small number of precipitates increased the yield strength. After ageing the alloy for the shortest period for which data were available, 8 min, clear evidence of precipitates could be found from the SAXS data, showing that the γ″-γ″- precipitates are about 6 nm in width and 3 nm in height.

  • 15.
    Fisk, Martin
    et al.
    Malmö högskola, School of Technology (TS).
    Ion, John C.
    Lindgren, Lars-Erik
    Flow stress model for IN718 accounting for evolution of strengthening precipitates during thermal treatment2014In: Computational materials science, ISSN 0927-0256, E-ISSN 1879-0801, Vol. 82, no 1, p. 531-539Article in journal (Refereed)
    Abstract [en]

    A flow stress model describing precipitate hardening in the nickel based alloy InconelÒ 718 following thermal treatment is presented. The interactions between precipitates and dislocations are included in a dislocation density based material model. Compression tests have been performed using solution annealed, fully-aged and half-aged material. Models were calibrated using data for solution annealed and fully-aged material, and validated using data from half-aged material. Agreement between experimental data and model predictions is good.

  • 16.
    Fisk, Martin
    et al.
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Division of Solid Mechanics, Lund University, P.O. Box 118, Lund, SE-221 00, Sweden.
    Lindgren, L. -E.
    Mechanics of Solid Materials, Luleå University of Technology, Luleå, SE-971 87, Sweden.
    Datchary, W.
    AB SKF, Gothenburg, SE-415 50, Sweden.
    Deshmukh, V.
    AB SKF, Gothenburg, SE-415 50, Sweden.
    Modelling of induction hardening in low alloy steels2018In: Finite elements in analysis and design (Print), ISSN 0168-874X, E-ISSN 1872-6925, Vol. 144, p. 61-75Article in journal (Refereed)
    Abstract [en]

    Induction hardening is a useful method for improving resistance to surface indentation, fatigue and wear that is favoured in comparison with through hardening, which may lack necessary toughness. The process itself involves fast heating by induction with subsequent quenching, creating a martensitic layer at the surface of the workpiece. In the present work, we demonstrate how to simulate the process of induction hardening using a commercial finite element software package with focuses on validation of the electromagnetic and thermal parts, together with evolution of the microstructure. Experiments have been carried out using fifteen workpieces that have been heated using three different heating rates and five different peak temperatures resulting in different microstructures. It is found that the microstructure and hardening depth is affected by the heating rate and peak temperature. The agreement between the experimental and simulated results is good. Also, it is demonstrated that the critical equilibrium temperatures for phase transformation is important for good agreement between the simulated and experimental hardening depth. The developed simulation technique predicts the hardness and microstructure sufficiently well for design and the development of induction hardening processes.

  • 17.
    Fisk, Martin
    et al.
    Malmö högskola, School of Technology (TS).
    Lindgren, Lars-Erik
    Physically based plasticity model coupled with precipitate model for IN7182012In: Proceedings of the 25TH NORDIC SEMINAR ON COMPUTATIONAL MECHANICS, Lund, 25-26 October, 2012, Lund University, Faculty of Engineering , 2012, p. 227-230Conference paper (Refereed)
    Abstract [en]

    This talk describes the nucleation, growth and coarsening of γ′′ precipitates in Inconel 718 (IN718) during heat treatments. The model can be used in thermo-mechanical simulations of repair welding followed by heat treatment to predict residual stresses and final microstructure in aeroengine components. The interactions between precipitates and dislocations are included in a dislocation density based material model.

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  • 18.
    Fisk, Martin
    et al.
    Malmö högskola, Faculty of Technology and Society (TS). Division of Solid Mechanics, Lund University, P.O. Box 118, Lund, SE-221 00, Sweden.
    Lundbäck, A.
    Mechanics of Solid Materials, Luleå University of Technology, Luleå, SE-971 87, Sweden.
    Edberg, J.
    Mechanics of Solid Materials, Luleå University of Technology, Luleå, SE-971 87, Sweden.
    Zhou, J. M.
    Division of Production and Materials Engineering, Lund University, P.O. Box 118, Lund, SE-221 00, Sweden.
    Simulation of microstructural evolution during repair welding of an IN718 plate2016In: Finite elements in analysis and design (Print), ISSN 0168-874X, E-ISSN 1872-6925, Vol. 120, p. 92-101Article in journal (Refereed)
    Abstract [en]

    A precipitate evolution model based on classical nucleation, growth and coarsening theory is adapted and solved using the multi-class approach for the superalloy IN718. The model accounts for dissolution of precipitates and is implemented in a finite element program. The model is used to simulate precipitate evolution in the fused zone and the adjacent heat affected zone for a welding simulation. The calculated size distribution of precipitates is used to predict Vickers hardness. The simulation model is compared with nanoindentation experiments. The agreement between simulated and measured hardness is good. (C) 2016 Elsevier B.V. All rights reserved.

  • 19.
    Fisk, Martin
    et al.
    Malmö högskola, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Lundbäck, Andreas
    Dept. of Eng. Sciences and Mathematics, Luleå University of Technology, SE-971 87, Luleå, Sweden.
    Andersson, Joel
    GKN Aerospace Engine Systems, SE-461 81 Trollhättan, Sweden; Department of Engineering Science, University West, SE-461 86 Trollhättan, Sweden; Department of Materials and Manufacturing Technology, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
    Lindgren, Lars-Erik
    Dept. of Eng. Sciences and Mathematics, Luleå University of Technology, SE-971 87, Luleå, Sweden.
    Finite Element Analysis using a Dislocation Density Based Flow Stress Model Coupled with Model for Precipitate Evolution2014In: 8th International Symposium on Superalloy 718 and Derivatives: Conference Proceedings, John Wiley & Sons, 2014, p. 155-168Conference paper (Refereed)
  • 20.
    Fisk, Martin
    et al.
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Division of Solid Mechanics, Lund University, P.O. Box 118, Lund SE-221 00, Sweden.
    Ristinmaa, Matti
    Division of Solid Mechanics, Lund University, P.O. Box 118, Lund SE-221 00, Sweden.
    Hultkrantz, Andreas
    AB SKF, Göteborg SE-415 50, Sweden.
    Lindgren, Lars-Erik
    Department of Engineering Sciences and Mathematics, Luleå University of Technology, Luleå SE-971 87, Sweden.
    Coupled electromagnetic-thermal solution strategy for induction heating of ferromagnetic materials2022In: Applied Mathematical Modelling, ISSN 0307-904X, E-ISSN 1872-8480, Vol. 111, p. 818-835Article in journal (Refereed)
    Abstract [en]

    Induction heating is used in many industrial applications to heat electrically conductive materials. The coupled electromagnetic-thermal induction heating process is non-linear in general, and for ferromagnetic materials it becomes challenging since both the electromagnetic and the thermal responses are non-linear. As a result of the existing non-linearities, simulating the induction heating process is a challenging task. In the present work, a coupled transient electromagnetic-thermal finite element solution strategy that is appropriate for modeling induction heating of ferromagnetic materials is presented. The solution strategy is based on the isothermal staggered split approach, where the electromagnetic problem is solved for fixed temperature fields and the thermal problem for fixed heat sources obtained from the electromagnetic solution. The modeling strategy and the implementation are validated against induction heating experiments at three heating rates. The computed temperatures, that reach above the Curie temperature, agree very well with the experimental results.

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  • 21.
    Haas, Sylvio
    et al.
    Photon Science, DESY, Hamburg, Germany.
    Andersson, Joel
    Department of Engineering Science, University West, Trollhättan, Sweden.
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Division of Solid Mechanics, Lund University, P.O. Box 118, Lund, SE-221 00, Sweden.
    Park, Jun-Sang
    X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, United States.
    Lienert, Ulrich
    Photon Science, DESY, Hamburg, Germany.
    Correlation of precipitate evolution with Vickers hardness in Haynes® 282® superalloy: In-situ high-energy SAXS/WAXS investigation2018In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 711, p. 250-258Article in journal (Refereed)
    Abstract [en]

    The aim of this work is to characterize the precipitation kinetics in Haynes® 282® superalloys using in-situ high-energy Small Angle X-ray Scattering (SAXS) together with Wide Angle X-ray Scattering (WAXS). The phases identified by WAXS include γ (matrix), γ′ (hardening precipitates), MC (metallic carbides), and M23C6/M6C (secondary metallic carbides). The γ’-precipitates are spheroids with a diameter of several nanometres, depending on the temperature and ageing time. From the SAXS data, quantitative parameters such as volume fraction, number density and inter-particle distance were determined and correlated with ex-situ Vickers microhardness measurements. The strengthening components associated with precipitates and solid solutions are differentiated using the measured Vickers microhardness and SAXS model parameters. A square root dependence between strengthening attributable to the precipitates and the product of volume fraction and mean precipitate radius is found. The solid solution strengthening component correlates with the total volume fraction of precipitates.

  • 22.
    Lindgren, Lars-Erik
    et al.
    Dept. of Eng. Sciences and Mathematics, Luleå University of Technology, 971 87 Luleå, Sweden.
    Fisk, Martin
    Malmö högskola, School of Technology (TS).
    Dislocation density based plasticity model coupled with precipitate model2013In: Advances in Engineering Plasticity XI, Trans Tech Publications, 2013, p. 125-128Conference paper (Refereed)
    Abstract [en]

    A dislocation density based plasticity model is applied to two variants of steels. One is an austenitic (fcc) stainless steel with ordered precipitates and the other is a Ti-Nb microalloyed (bcc) steel. Precipitate distributions are measured and this information is combined with appropriate precipitate hardening models. The flow stress model is also calibrated for an nickel-based superalloy where it is combined with a model for precipitate growth.

  • 23. Lindgren, Lars-Erik
    et al.
    Lundbäck, Andreas
    Fisk, Martin
    Malmö högskola, School of Technology (TS).
    Thermo-Mechanics and Microstructure Evolution in Manufacturing Simulations2013In: Journal of thermal stresses, ISSN 0149-5739, E-ISSN 1521-074X, Vol. 36, no 6, p. 564-588Article in journal (Refereed)
    Abstract [en]

    Thermal stresses and deformations are present and important for many manufacturing processes. Their effect depends strongly on the material behavior. The finite element method has been applied successfully for manufacturing simulations. There are numerical challenges in some cases due to large deformations, strong non-linearities etc. However, the most challenging aspect is the modeling of the material behavior. This requires in many cases coupled constitutive and microstructure models.

  • 24.
    Lindgren, Lars-Erik
    et al.
    Luleå University of Technology, 971 87 Luleå, Sweden.
    Lundbäck, Andreas
    Luleå University of Technology, 971 87 Luleå, Sweden.
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Draxler, Joar
    Luleå University of Technology, 971 87 Luleå, Sweden.
    Modelling additive manufacturing of superalloys2019In: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 35, p. 252-258Article in journal (Refereed)
    Abstract [en]

    There exist several variants of Additive Manufacturing (AM) applicable for metals and alloys. The two main groups are Directed Energy Deposition (DED) and Powder Bed Fusion (PBF). AM has advantages and disadvantages when compared to more traditional manufacturing methods. The best candidate products are those with complex shape and small series and particularly individualized product. Repair welding is often individualized as defects may occur at various instances in a component. This method was used before it became categorized as AM and in most cases, it is a DED process. PBF processes are more useful for smaller items and can give a finer surface. Both DED and PBF products require subsequent surface finishing for high performance components and sometimes there is also a need for post heat treatment. Modelling of AM as well as eventual post-processes can be of use in order to improve product quality, reducing costs and material waste. The paper describes the use of the finite element method to simulate these processes with focus on superalloys. 

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  • 25.
    Lindgren, Lars-Erik
    et al.
    Luleå University of Technology, Luleå, 971 87, Sweden.
    Lundbäck, Andreas
    Luleå University of Technology, Luleå, 971 87, Sweden.
    Fisk, Martin
    Malmö högskola, Faculty of Technology and Society (TS).
    Pederson, Robert
    GKN Aerospace Engine Systems, Trollhättan, 461 81, Sweden.
    Andersson, Joel
    University West, Trollhättan, 461 86, Sweden.
    Simulation of additive manufacturing using coupled constitutive and microstructure models2016In: Additive Manufacturing, ISSN 2214-8604, E-ISSN 2214-7810, Vol. 12, no Part B : Special Issue on Modeling & Simulation for Additive Manufacturing, p. 144-158Article in journal (Refereed)
    Abstract [en]

    The paper describes the application of modeling approaches used in Computational Welding Mechanics (CWM) applicable for simulating Additive Manufacturing (AM). It focuses on the approximation of the behavior in the process zone and the behavior of the solid material, particularly in the context of changing microstructure. Two examples are shown, one for the precipitation hardening Alloy 718 and one for Ti-6Al-4V. The latter alloy is subject to phase changes due to the thermal cycling. (C) 2016 Elsevier B.V. All rights reserved.

  • 26.
    Lindwall, Johan
    et al.
    Lulea Univ Technol, Dept Engn Sci & Math, SE-97187 Lulea, Sweden..
    Ericsson, Anders
    Lund Univ, Div Solid Mech, Box 118, SE-22100 Lund, Sweden..
    Marattukalam, Jithin James
    Uppsala Univ, Dept Phys & Astron, Box 538, SE-75121 Uppsala, Sweden..
    Hassila, Carl-Johan
    Uppsala Univ, Dept Mat Sci & Engn, Box 538, SE-75121 Uppsala, Sweden..
    Karlsson, Dennis
    Uppsala Univ, Dept Chem, Angstrom Lab, Box 538, SE-75121 Uppsala, Sweden.;Sandvik Mat Technol, SE-81181 Sandviken, Sweden..
    Sahlberg, Martin
    Uppsala Univ, Dept Chem, Angstrom Lab, Box 538, SE-75121 Uppsala, Sweden..
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Lund Univ, Div Solid Mech, Box 118, SE-22100 Lund, Sweden.;Malmö Univ, Mat Sci & Appl Math, SE-20506 Malmö, Sweden..
    Lundbäck, Andreas
    Lulea Univ Technol, Dept Engn Sci & Math, SE-97187 Lulea, Sweden..
    Simulation of phase evolution in a Zr-based glass forming alloy during multiple laser remelting2022In: JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T, ISSN 2238-7854, Vol. 16, p. 1165-1178Article in journal (Refereed)
    Abstract [en]

    Additive manufacturing by laser-based powder bed fusion is a promising technique for bulk metallic glass production. But, reheating by deposition of subsequent layers may cause local crystallisation of the alloy. To investigate the crystalline phase evolution during laser scanning of a Zr-based metallic glass-forming alloy, a simulation strategy based on the finite element method and the classical nucleation theory has been developed and compared with experimental results from multiple laser remelting of a single-track. Multiple laser remelting of a single-track demonstrates the crystallisation behaviour by the influence of thermal history in the reheated material. Scanning electron microscopy and transmission electron microscopy reveals the crystalline phase evolution in the heat affected zone after each laser scan. A trend can be observed where repeated remelting results in an increased crystalline volume fraction with larger crystals in the heat affected zone, both in simulation and experiment. A gradient of cluster number density and mean radius can also be predicted by the model, with good correlation to the experiments. Prediction of crystallisation, as presented in this work, can be a useful tool to aid the development of process parameters during additive manufacturing for bulk metallic glass formation.(c) 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

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  • 27. Lundbäck, Andreas
    et al.
    Fisk, Martin
    Malmö högskola, School of Technology (TS).
    Repair welding and local heat treatment2014In: Encyclopedia of Thermal Stresses / [ed] Richard B Hetnarski, Springer, 2014, p. 4186-4194Chapter in book (Other academic)
    Abstract [en]

    One application for repair welding is to restore the integrity of a component where a crack has been found. Cracks can appear during in-service or already in the manufacturing process. The latter is usually the case for large castings where cracks may have formed. The repair welding in this entry is the process of filling a premachined slot. This slot has been milled in order to remove the crack that has been found. The welding process can be any kind of arc, beam, or gas welding process. However, manual arc welding is the most common method for repair welding. Thereafter, the component may need to be heat treated in order to reduce residual stresses and/or restore material microstructure. Local heat treatment means that only a part of the structure is heat treated. This is in contrast to global heat treatment where the entire structure is heat treated by placing it in a furnace. We focus on the use of induction heating for local heat treatment in the current entry.

  • 28.
    Malmelöv, Andreas
    et al.
    Division of Mechanics of Solid Materials, Luleå University of Technology, SE-971 87 Luleå, Sweden.
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Division of Solid Mechanics, Lund University, P.O. Box 118, SE-221 00 Lund, Sweden.
    Lundbäck, Andreas
    Division of Mechanics of Solid Materials, Luleå University of Technology, SE-971 87 Luleå, Sweden.
    Lindgren, Lars-Erik
    Division of Mechanics of Solid Materials, Luleå University of Technology, SE-971 87 Luleå, Sweden.
    Mechanism Based Flow Stress Model for Alloy 625 and Alloy 718.2020In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 13, no 24, article id E5620Article in journal (Refereed)
    Abstract [en]

    To predict the final geometry in thermo-mechanical processes, the use of modeling tools is of great importance. One important part of the modeling process is to describe the response correctly. A previously published mechanism-based flow stress model has been further developed and adapted for the nickel-based superalloys, alloy 625, and alloy 718. The updates include the implementation of a solid solution strengthening model and a model for high temperature plasticity. This type of material model is appropriate in simulations of manufacturing processes where the material undergoes large variations in strain rates and temperatures. The model also inherently captures stress relaxation. The flow stress model has been calibrated using compression strain rate data ranging from 0.01 to 1 s−1 with a temperature span from room temperature up to near the melting temperature. Deformation mechanism maps are also constructed which shows when the different mechanisms are dominating. After the model has been calibrated, it is validated using stress relaxation tests. From the parameter optimization, it is seen that many of the parameters are very similar for alloy 625 and alloy 718, although it is two different materials. The modeled and measured stress relaxation are in good agreement.

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  • 29.
    Malmelöv, Andreas
    et al.
    Lulea Univ Technol, Mech Solid Mat, SE-97187 Lulea, Sweden..
    Hassila, Carl-Johan
    Uppsala Univ, Appl Mat Sci, SE-75103 Uppsala, Sweden..
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Division of Solid Mechanics, Lund University, P.O. Box 118, Lund, SE-221 00, Sweden.
    Wiklund, Urban
    Uppsala Univ, Appl Mat Sci, SE-75103 Uppsala, Sweden..
    Lundbäck, Andreas
    Lulea Univ Technol, Mech Solid Mat, SE-97187 Lulea, Sweden..
    Numerical modeling and synchrotron diffraction measurements of residual stresses in laser powder bed fusion manufactured alloy 6252022In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 216, article id 110548Article in journal (Refereed)
    Abstract [en]

    Residual stresses in metal additive manufactured components are a well-known problem. It causes dis-tortion of the samples when removing them from the build plate, as well as acting detrimental with regard to fatigue. The understanding of how residual stresses in a printed sample are affected by process parameters is crucial to allow manufacturers to tune their process parameters, or the design of their com-ponent, to limit the negative influence of residual stresses. In this paper, residual stresses in additive manufactured samples are simulated using a thermo-mechanical finite element model. The elasto-plastic behavior of the material is described by a mechanism-based material model that accounts for microstructural and relaxation effects. The heat source in the finite element model is calibrated by fitting the model to experimental data. The residual stress field from the finite element model is compared with experimental results attained from synchrotron X-ray diffraction measurements. The results from the model and measurement give the same trend in the residual stress field. In addition, it is shown that there is no significant difference in trend and magnitude of the resulting residual stresses for an alterna-tion in laser power and scanning speed.(c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

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  • 30.
    Reheman, Wureguli
    et al.
    Department of Mechanical Engineering, Blekinge Institute of Technology, Karlskrona, Sweden.
    Ståhle, Per
    Solid Mechanics, Lund University, Lund, Sweden.
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Singh, Ram Niwas
    Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
    On the formation of expanding crack tip precipitates2019In: International Journal of Fracture, ISSN 0376-9429, E-ISSN 1573-2673, Vol. 217, no 1-2, p. 35-48Article in journal (Refereed)
    Abstract [en]

    The stress driven growth of an expanding precipitate at a crack tip is studied. The material is assumed to be linearly elastic, and the expansion is considered to be isotropic or transversely isotropic. The extent of the precipitate is expected to be small as compared with the crack length and distance to boundaries. The problem has only a single length scale given by the squared ratio of the stress intensity factor and a critical hydrostatic stress that initiates the growth of the precipitate. Therefore, the growth occurs under self-similar conditions. The equations on non-dimensional form show that the free parameters are expansion strain, degree of anisotropy and Poisson's ratio. It is found that the precipitate, once initiated, grows without remote load for expansion strains above a critical value. The anisotropy of the expansion strongly affects the shape of the precipitate but does not have a large effect on the crack tip shielding.

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  • 31.
    Reheman, Wureguli
    et al.
    Mechanical Engineering Dept., Blekinge Institute of Technology, Karlskrona, Sweden.
    Ståhle, Per
    Solid Mechanics, LTH, Lund University, SE22100 Lund, Sweden.
    Singh, Ram N.
    Bhabha Atomic Research Centre, Mumbai-400085, Mumbai, India.
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Stable and unstable growth of crack tip precipitates2018In: Procedia Structural Integrity, ISSN 2452-3216, Vol. 13, p. 1792-1797Article in journal (Refereed)
    Abstract [en]

    A model is established that describes stress driven diffusion, resulting in formation and growth of an expanded precipitate at the tip of a crack. The new phase is transversely isotropic. A finite element method is used and the results are compared with a simplified analytical theory. A stress criterium for formation of the precipitate is derived by direct integration of the Einstein-Smoluchowski law for stress driven diffusion. Thus, the conventional critical concentration criterium for precipitate growth can be replaced with a critical hydrostatic stress. The problem has only one length scale and as a consequence the precipitate grows under self-similar conditions. The length scale is given by the stress intensity factor, the diffusion coefficient and critical stress versus remote ambient concentrations. The free parameters involved are the expansion strain, the degree of anisotropy and Poisson's ratio. Solutions are obtained for a variation of the first two. The key result is that there is a critical phase expansion strain below which the growth of the new phase is stable and controlled by the stress intensity factor. For supercritical expansion strains, the precipitate grows even without remote load. The anisotropy of the expansion strongly affects the shape of the precipitate, but does not have a large effect on the crack tip shielding. (C) 2018 The Authors. Published by Elsevier B.V.

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  • 32.
    Tidefelt, Mattias
    et al.
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM).
    Löstrand, Julia
    Uppsala Univ, Div Mat Phys, Dept Phys & Astron, Box 530, SE-75121 Uppsala, Sweden..
    Goetz, Inga K.
    Uppsala Univ, Div Mat Phys, Dept Phys & Astron, Box 530, SE-75121 Uppsala, Sweden..
    Donzel-Gargand, Olivier
    Uppsala Univ, Div Solar Cell Technol, Dept Mat Sci & Engn, Angstrom Solar Ctr, S-75121 Uppsala, Sweden..
    Ericsson, Anders
    Lund Univ, Div Solid Mech, POB 118, SE-22100 Lund, Sweden..
    Han, Xiaoliang
    Leibniz Inst Solid State & Mat Res, Helmholtzstr 20, D-01069 Dresden, Germany..
    Joensson, Petra E.
    Uppsala Univ, Div Mat Phys, Dept Phys & Astron, Box 530, SE-75121 Uppsala, Sweden..
    Sahlberg, Martin
    Uppsala Univ, Dept Chem, Angstrom Lab, Box 538, SE-75121 Uppsala, Sweden..
    Kaban, Ivan
    Leibniz Inst Solid State & Mat Res, Helmholtzstr 20, D-01069 Dresden, Germany..
    Fisk, Martin
    Malmö University, Faculty of Technology and Society (TS), Department of Materials Science and Applied Mathematics (MTM). Lund Univ, Div Solid Mech, POB 118, SE-22100 Lund, Sweden..
    In Situ Mapping of Phase Evolutions in Rapidly Heated Zr-Based Bulk Metallic Glass with Oxygen Impurities2024In: Advanced Science, E-ISSN 2198-3844, Vol. 11, no 16Article in journal (Refereed)
    Abstract [en]

    Metallic glasses exhibit unique mechanical properties. For metallic glass composites (MGC), composed of dispersed nanocrystalline phases in an amorphous matrix, these properties can be enhanced or deteriorated depending on the volume fraction and size distribution of the crystalline phases. Understanding the evolution of crystalline phases during devitrification of bulk metallic glasses upon heating is key to realizing the production of these composites. Here, results are presented from a combination of in situ small- and wide-angle X-ray scattering (SAXS and WAXS) measurements during heating of Zr-based metallic glass samples at rates ranging from 102 to 104 Ks-1 with a time resolution of 4ms. By combining a detailed analysis of scattering experiments with numerical simulations, for the first time, it is shown how the amount of oxygen impurities in the samples influences the early stages of devitrification and changes the dominant nucleation mechanism from homogeneous to heterogeneous. During melting, the oxygen rich phase becomes the dominant crystalline phase whereas the main phases dissolve. The approach used in this study is well suited for investigation of rapid phase evolution during devitrification, which is important for the development of MGC. Oxygen impurities impact on phase-transformations during rapid heating of Zr-based metallic glass Zr59.3Cu28.8Al10.4Nb1.5 is thoroughly investigated using a multi-technique approach. During devitrification, the extracted phase evolutions reveal that the phase fraction hierarchy correlates with the oxygen impurity concentration. Numerical simulations with a heterogeneous nucleation mode capture the experimental observations. During melting, the oxygen-rich phase becomes the dominant phase. image

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