采用双通道等径侧面挤压法提高 AA5083铝合金力学性能

摘要

Dual equal channel lateral extrusion (DECLE), as a severe plastic deformation (SPD) process, was employed for improving the mechanical properties of AA5083 aluminum alloy. Several experiments were conducted to study the influences of the route type, namely A and B, and pass number on mechanical properties of the material. The process was conducted up to 6 passes with decreasing process temperature, specifically from 573 to 473 K. Supplementary experiments involving metallography, hardness and tensile tests were carried out in order to evaluate the effects of the process variables. The hardness measurements exhibited reasonably uniform distributions within the product with a maximum increase of 64% via a 6-pass operation. The yield and ultimate strengths also amended 107% and 46%, respectively. These significant improvements were attributed to the severe shear deformation of grains and decreasing pass temperature, which intensified the grain refinement. TEM images showed an average grain size reduction from 100 µm for the annealed billet to 200 nm after 6 passes of DECLE. Finally, the experimental findings for routes A and B were compared and discussed and some important conclusions were drawn.%采用双通道等径侧面挤压剧烈塑性变形工艺提高 AA5083铝合金的力学性能。采用多组实验研究路径类型(A 和 B 路径)和挤压道次对材料力学性能的影响。挤压道次为6道次，挤压温度范围为573~473 K，采用金相、硬度测试和拉伸测试研究这些工艺参数的影响。硬度测试表明经6道次挤压后，硬度提高了64%，且分布均匀。屈服强度和抗拉强度分别提高了107%和46%。这是由于晶粒的剧烈剪切变形和变形温度降低导致的晶粒细化。TEM 结果表明，经 DECLE 6道次变形后，合金的平均晶粒尺寸从退火态的100μm 减小至200 nm。对比研究了路径 A 和 B 的实验结果，并得到一些重要结论。