(合肥工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，合肥 230009)
摘 要: 對純鋁粉末材料進行200 ℃單道次等徑角擠扭(ECAPT)變形實驗研究。采用光學(xué)顯微鏡(OM)、電子背散射技術(shù)(EBSD)和透射電子顯微鏡(TEM)觀察和分析變形組織微觀結(jié)構(gòu)的變化規(guī)律，獲得有關(guān)晶粒形貌、晶粒尺寸以及晶粒取向分布的信息。結(jié)果表明：ECAPT工藝對粉末材料具有強烈的致密和細化效果，1道次ECAPT變形后組織接近完全致密，晶粒細化效果明顯，平均晶粒尺寸約為5.2 μm；晶粒尺寸分布不均勻，亞晶界和小角度晶界所占比例較高；變形組織內(nèi)部形成了明顯的擇優(yōu)取向，沿剪切方向均勻?qū)ΨQ分布，以剪切織構(gòu)類型為主；200 ℃條件下，純鋁粉末材料單道次ECAPT變形過程中，晶粒的顯著細化主要得益于材料組織所承受的劇烈剪切變形和內(nèi)部所累積的大量有效應(yīng)變。
關(guān)鍵字: 粉末材料；純鋁粉末；等徑角擠扭；微觀結(jié)構(gòu)；致密；晶粒細化
（School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China）
Abstract:Pure Al particles were successfully consolidated into nearly dense bulk materials by equal channel angular pressing and torsion (ECAPT) at 200 ℃. The microstructures were characterized using OM, EBSD and TEM for grain shape and size as well as misorientations. The results show that ECAPT is an effective technique and has potential in consolidating and refining the microstructures of powder materials. The consolidated material shows a fine structure with the grain size of around 5.2 μm, while the distribution of the grain size is not uniform. The microstructure mainly consists of elongated subgrains of low angle boundaries and fine equiaxed grains of high angle boundaries. In addition, there is a strong shear texture after 1 pass ECAPT. The grain refinement mechanism during a single pass of ECAPT is attributed to intensive shearing and large accumulated strain
Key words: powder particles; pure particles; equal channel angular torsion; microstructure; densification; grain refinement
