Simulation on Nanostructured Metals Based on Multiscale Crystal Plasticity Considering Effect of Grain Boundary

2012 ◽  
Vol 706-709 ◽  
pp. 1751-1756 ◽  
Author(s):  
Yoshiteru Aoyagi ◽  
Tomotsugu Shimokawa ◽  
Kazuyuki Shizawa ◽  
Yoshiyuki Kaji
Keyword(s):  
Grain Boundary ◽  
Crystal Plasticity ◽  
High Strength ◽  
Nanostructured Metals ◽  
Hardening Law ◽  
Crystal Plasticity Model ◽  
Ultrafine Grained ◽  
Dislocation Behavior ◽  
Strain Responses ◽  
Peculiar Behavior

Ultrafine-grained metals whose grain size is less than one micron have attracted interest as high strength materials. Whereas nanostructured metals produced by severe plastic deformation express remarkably peculiar behavior in both material and mechanical aspects, its mechanism has been clarified by neither experimental nor computational approaches. In this study, we develop a multiscale crystal plasticity model considering an effect of grain boundary. In order to express release of dislocation from grain boundaries, information of misorientation is introduced into a hardening law of crystal plasticity. In addition, carrying out FE simulation for FCC polycrystal, the stress-strain responses such as increase of yield stress due to existence of grain boundary are discussed. We investigate comprehensively the effect of dislocation behavior on the material property of nanostructured metal.

Multiscale Simulation of Dynamic Recrystallization for α-Mg Phase in Mg/LPSO Alloys Based on Multi-Phase-Field and Dislocation-Based Crystal Plasticity Model

2016 ◽  
Vol 725 ◽  
pp. 243-248
Author(s):  
Yuichi Kimura ◽  
Sho Kujirai ◽  
Ryo Ueta ◽  
Kazuyuki Shizawa
Keyword(s):  
Grain Boundary ◽  
Dynamic Recrystallization ◽  
Crystal Plasticity ◽  
Phase Field ◽  
Boundary Segregation ◽  
Multiscale Simulation ◽  
Plasticity Model ◽  
Lpso Phase ◽  
Crystal Plasticity Model ◽  
Multi Phase

Magnesium alloy with Long-Period Stacking Ordered Structure (LPSO) and α-Mg (ordinary HCP structure) phase is expected for a new structural material due to its excellent mechanical properties. Its materials strengthening arises from the kink band formation in LPSO phase and the grain refinement of α-Mg phase in the vicinity of LPSO phase because of recrystallization. In the present study, a multiscale and multiphysics computation for the dynamic recrystallization in α-Mg phase is carried out by coupling the dislocation-based crystal plasticity model for HCP crystals proposed previously by the authors with the multi-phase field model through dislocation density. In the present model, not only the environmental temperature-dependences of nucleation and nucleus growth but also a pinning effect of boundary migration of recrystallized grain boundary owing to existence and influence of additive elements are newly taken into account. Furthermore, grain size behaviors of recrystallized nuclei are investigated for various volume fractions of additive element and ratios of grain boundary segregation.

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