(合肥工業(yè)大學 材料科學與工程學院, 合肥 230009)
摘 要: 等徑角擠壓是獲得塊體超細晶材料的一種重要工藝方法。 針對粉末多孔材料， 采用體積可壓縮剛粘塑性熱力耦合有限元法對其等徑角擠壓過程進行模擬分析。 結(jié)果顯示， 等徑角擠壓工藝對粉末多孔材料具有強烈的致密效果， 變形溫度和接觸摩擦狀況對變形及致密存在明顯的影響。 研究表明， 材料所處的靜水壓力狀態(tài)對多孔材料的擠壓效果影響顯著， 高的靜水壓力狀態(tài)有利于提高粉末材料的變形能力及致密效果， 改進的帶背壓工藝有利于提高變形的均勻性, 擴大工藝的應用范圍。
關鍵字: 粉末多孔材料； 等徑角擠壓； 熱力耦合； 有限元分析； 靜水壓力
（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
