等径角挤压7075铝合金的显微组织和织构演变

摘要

Equal channel angular pressing is an effective technique to control the texture and microstructure of metals and alloys. Texture and microstructure of an Al-7075 alloy subjected to repetitive equal channel angular pressing through a 90° die were evaluated by X-ray diffractometer and orientation imaging microscopy. It is observed that processing through different routes leads to different types of textures, in both qualitative and quantitative senses. The texture calculation by Labotex software reveals that texture strengthens after the first pass and weakens by progressing ECAP process up to 4 passes. Microstructure investigations show that after 4 passes of equal channel angular pressing via routes BC and A, very fine grains with average grain size of about 700 nm and 1μm appear, respectively, and most of the grains evolve into arrays of high angle boundaries. The effects of covering the Al-7075 billets with copper tube on texture and microstructure were also studied.%等径角挤压是一种有效的控制金属和合金显微组织和织构的技术.采用X射线衍射仪和取向成像显微镜评价通过90°模具反复等径角挤压7075铝合金的显微组织和织构.定性和定量分析结果表明,不同的路径会产生不同的织构类型.利用Labotex软件计算的织构表明,经第1道次等径角挤压后合金织构增强,而经第4道次挤压后合金织构减弱.显微组织研究表明,经过Bc和A路径等径角挤压4道次后,出现了平均尺寸分别为700 nm和1μm 的细小晶粒,且大多数晶粒演化为大角度晶界排列.研究了铜管包覆对7075铝合金显微组织和织构的影响.