(合肥工业大学 材料科学与工程学院, 合肥 230009)
摘 要: 等径角挤压是获得块体超细晶材料的一种重要工艺方法。 针对粉末多孔材料， 采用体积可压缩刚粘塑性热力耦合有限元法对其等径角挤压过程进行模拟分析。 结果显示， 等径角挤压工艺对粉末多孔材料具有强烈的致密效果， 变形温度和接触摩擦状况对变形及致密存在明显的影响。 研究表明， 材料所处的静水压力状态对多孔材料的挤压效果影响显著， 高的静水压力状态有利于提高粉末材料的变形能力及致密效果， 改进的带背压工艺有利于提高变形的均匀性, 扩大工艺的应用范围。
关键字: 粉末多孔材料； 等径角挤压； 热力耦合； 有限元分析； 静水压力
（School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China）
Abstract: The purpose of equal channel angular pressing (ECAP) is to obtain ultra-fine grained (UFG) materials. The densification and deformation behavior of porous materials during the ECAP process were investigated by thermo-mechanical coupling finite element method. The distributions of temperature, strain, relative density and stress of specimen were obtained. The results show that the ECAP process is a useful tool to eliminate the porosities and more effective in high temperature and friction conditions. The finite element analysis shows that the hydrostatic stress state has important effect on the result. It is beneficial to improve the ductility and density of material with porosities in high hydrostatic stress state. And the back pressure applied to the ECAP can greatly increase the strain level, while can not reduce the uniformity of the strain distribution.
Key words: porous materials; equal channel angular pressing; thermo-mechanical coupling; finite element analysis; hydrostatic stress
