挤压道次对等通道转角挤压高纯铝微观组织的影响  

Influence of extrusion pass on microstructure for ECAP high purity aluminum

作　　者：孙杰英 Sun Jieying(Manufacturing Engineering Technology Center,GAC FIAT CHRYSLER Automobiles Co.,Ltd.,Changsha 410131,China)

机构地区：[1]广汽菲亚特克莱斯勒汽车有限公司工艺技术部,湖南长沙410131

出　　处：《锻压技术》2023年第3期163-169,共7页Forging & Stamping Technology

摘　　要：采用等通道转角挤压工艺,在常温下对高纯铝进行5道次挤压变形。利用透射电子显微镜和电子背散射衍射技术,对等通道转角挤压后高纯铝的组织结构、微观织构和晶界特征进行表征,研究挤压道次对等通道转角挤压高纯铝微观组织的影响以及挤压后材料组织的演化机制。结果表明:随着挤压道次的增加,材料剪切变形抗力不断增加;5道次变形后,材料晶粒得到显著细化,形成多边界平直、低位错密度的等轴状晶粒,晶粒尺寸约为0.9μm。同时,挤压5道次后材料的晶粒取向逐渐变得随机,微观织构在(80°, 35°, 0°)、(40°, 75°, 45°)和(0°, 85°, 45°)达到峰值;超细晶高纯铝晶界是几何必须晶界,挤压后超细晶的形成是连续动态再结晶的结果。The equal channel angular pressing(ECAP)process was used,and the five-pass extrusion deformation of high purity aluminum was conducted at room temperature.Then,the microstructure,microtexture and grain boundary characteristics of the high purity aluminum processed by ECAP were investigated by means of TEM and EBSD,and the influences of extrusion pass on the microstructure of high purity aluminum after ECAP processing and the evolution mechanism of material structure after estrusion were studied.The results indicate that the shear deformation resistance of the material continuously increases with the increasing of extrusion passes.After five passes of deformation,the grains of the material are significantly refined,forming equiaxed grains with mulit-boundary straight and low dislocation density,and the grain size is about 0.9μm.At the same time,after five passes of extrusion,the grain orientation of material gradually becomes random,and the microtextures at(80°,35°,0°),(40°,75°,45°)and(0°,85°,45°)reaches the peak value.The grain boundary of ultra-fine-grained high-purity aluminum is a geometrically necessary grain boundary,and the formation of ultra-fine grains after extrusion is the result of continuous dynamic recrystallization.

关 键 词：等通道转角挤压 高纯铝 晶粒细化 微观织构 挤压道次 

分 类 号：TG146.2[一般工业技术—材料科学与工程]