Polycrystal plasticity simulation of extrusion of a magnesium alloy round bar: Effect of strain path non-uniformity
Polycrystal plasticity simulation of extrusion of a magnesium alloy round bar: Effect of strain path non-uniformity
复制标题
DOI：
10.1016/j.jallcom.2017.09.162
复制
发表时间：
2018-01
影响因子：
6.2
通讯作者：
Tao Tang;Yichuan Shao;Dayong Li;L. Peng;Ying-hong Peng;S. Zhang;Peidong Wu
中科院分区：
文献类型：
--
作者：
Tao Tang;Yichuan Shao;Dayong Li;L. Peng;Ying-hong Peng;S. Zhang;Peidong Wu
建立流线模型，并结合晶体塑性方法模拟镁合金圆棒的挤压过程，研究应变路径不均匀性对挤压过程中织构和显微组织发展的影响。建立了参数化的流线模型，描述了挤压腔内不同应变路径下的材料流动。采用多晶塑性方法和动态再结晶唯象模型分析了变形过程中织构和显微组织的演变。在挤压中心附近变形的材料在（0001）极图中呈现出典型的环状纤维织构，而在挤压侧边变形的材料基极由于孪晶和滑移系的活动增加而倾向于向挤压方向反向旋转。由于较高的应变速率，在侧部区域获得更细化的组织。通过模拟不同挤压织构的拉伸和压缩过程，研究了挤压棒材中心区和侧边区力学性能的差异。侧面材料比中心材料具有更好的各向同性力学性能，因此在压缩过程中孪晶的作用较小。
A flow line model is established and combined with the crystal plasticity method to simulate the extrusion process of a magnesium alloy round bar, and investigate the effect of strain path non-uniformity on development of texture and microstructure in extrusion. A parametric flow line model is established to characterize the material flow corresponding to different strain paths in the extrusion chamber. The polycrystal plasticity method coupled with a phenomenological dynamic recrystallization model is employed to analyze the evolution of texture and microstructure accompanying the deformation. The texture of material deformed near the central extrusion area shows the typical ring fiber texture in the (0001) pole figure, while the basal poles of the material deformed in the side areas tend to rotate backward to the extrusion direction, resulting from an increase of the activities of twinning and slip systems. The more refined microstructure is obtained in the side areas due to the higher strain rate. The difference of mechanical properties between center and side areas of the extruded bar are numerically investigated by simulating tension and compression by using different extrusion textures. Side material shows more isotropic mechanical property than central material, and then less twinning is operative in compression.