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Modelling the Microstructure Morphology and Material Properties of High Performance Alloys



The macroscopic behaviour of metallic components is governed by the morphology and behaviour of the microstructural constituents. To optimise the performance of modern engineering materials it is essential to gain a physical based understanding of the relevant deformation and damage mechanisms. Due to complex interdependencies during material processing, it is impossible to study the effect of different microstructural features on the global component behaviour solely by experimental characterisation methods. Furthermore saving time and costs, the validated and verified computationally aided simulation of material behaviour plays an increasingly important role in modern material design. Within the scope of this contribution, special emphasise is dedicated to the widely used Ni-based cast alloys, AHS steels and Ti-based alloys Spatially inhomogeneous solidification conditions within Ni-based cast parts cause the formation of micro-voids. Capturing the local curvature of pores and the overall void volume fraction by distributions of primitive geometries facilitates to quantify the deterioration of properties of porous material as compared to pore-free material. The remarkable macroscopic behaviour of dual-phase steels is due to placement of hard martensite within a soft ferritic matrix. Modelling the grain morphology by a Voronoï tessellation and the phase specific constitutive behaviour by Hall-Petch type relations enables to predict the formability and damage tolerance of these AHS steels. The Johnson-Mehl tessellation provides an adequate morphological description of Ti-base alloys featuring a duplex microstructure. Studying the distribution and redistribution of residual stresses during processing allows improving the accuracy of life time prediction of engineering components subjected to cyclic loading. Hence, multiscale material modelling techniques combined with a fully automated computer generation of microstructures provide a flexible and robust tool to study material and component behaviour by taking into account processing characteristics and microstructural features.


Representative Volume Element, Micro-mechanical modelling, AHS Steels, Ni-base cast alloys, Ti-base alloysText

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