工艺路线对等径角挤压变形均匀性的影响

等径角挤压被认为是制备块体超细晶材料最有前景的工艺方法之一.采用刚塑性有限元法分析了不同路线多道次等径角挤压后的等效应变分布.结果表明:一道次等径角挤压后坯料中间主要变形区下部坯料的等效应变较低.A路线多道次挤压后,变形更加不均匀,上下表面的等效应变差值增大;C路线挤压后等效应变分布呈上下表面小,中间较高的分布特征,且随挤压次数的增加,中心和上下表面的等效应变差异增大.B_c路线多次挤压后的等效应变分布较均匀,等效应变较高的区域应变相差较小且所占区域较大.模拟结果对于等径角挤压工艺的制定可起到指导作用.

Influence of Process Routes on Strain Homogeneity During Equal Channel Angular Pressing

Equal channel angular pressing (ECAP) is regarded as one of the most promising process of fabricating bulk ultra-fine grain materials. The effective strain in the billet was analyzed by rigid plastic finite element method during multipass equal channel angular press with different routes. The results show that the effective strain at the bottom part of the middle main deformation zone is low after 1 pass ECAP. The effective strain becomes more inhomogeneous after multipass ECAP by route A, and the difference of effective strain between the bottom and top surface part increases. The effective strain at the top and bottom surface part is lower, and the center part is higher after multipass ECAP by route C. The effective stain distribution is more homogeneous after ECAP by route B_c than other routes, and the difference at the high effective strain zone is low, and the fraction of the high effective strain zone is bigger. The simulation results can instruct the technology establishment during equal channel angular press.