中文摘要：

采用体积可压缩刚粘塑性有限元法对粉末多孔材料带反压的等通道转角挤压过程进行数值模拟，获得粉末多孔材料在该过程中的变形和致密行为。并在此基础上分析反压大小和反压模具结构对挤压变形效果的影响。结果表明：采用带反压的方式可有效控制变形过程中粉末金属的流动，增加试件整体变形的变形量，提高变形均匀性及致密效果；带反压的等通道转角挤压工艺可有效降低试件在挤压过程中产生破坏的可能性，同无反压方式相比，带反压挤压件内部获得更为均匀细密的内部组织结构。

英文摘要：

The densification and deformation behavior of powder porous material during the equal channel angular extrusion （ECAE） process with back pressure were investigated by compressible rigid-viscoplasticity finite element method. Based on the numerical results, the distribution of strain, relative density of specimen was obtained. The finite element analysis results show that back pressure has important effect on the extrusion result. It can not only improve the ductility and density of powder porous material, but also greatly increase the strain level and the uniformity of the strain distribution. The ECAE with back pressure can reduce the destruction of specimen and obtain much more homogenous and finer grain.