Al-Zn-Mg-Cu合金新型等通道转角双向镦挤变形行为分析

Deformation behavior analysis of Al-Zn-Mg-Cu Alloy Processed by Equal Channel Angular Dual-directional Extrusion

摘要:

以超高强度Al-Zn-Mg-Cu合金为研究对象，采用数值模拟和实验相结合的方法对其等通道转角双向镦挤过程进行分析。结果发现，变形过程可以分为近局部镦粗、剪切变形、最后填充三个阶段，变形结束后试样根据金属流动和网格畸变程度划分为小变形区、不变形区、剪切变形区、剧烈变形区。不同加载方式使变形区域发生不同程度偏移，上下冲头速度差越大，变形均匀性越差，速度比为1时可获得最大的应变量为3.97，且变形均匀性系数最低为1.89。同时，对不同路径下的多道次变形行为进行研究，发现4道次结束后，B路径比A路径变形更加均匀充分，其变形均匀性系数降低了29 %，剪切变形区占比提升了14 %。

Abstract:

The deformation behavior of Al-Zn-Mg-Cu alloy during equal channel angular dual-directional extrusion （ECADE） processing was studied by means of numerical simulation and experiments. The results show that the ECADE process can be divided into three stages: local upsetting, shearing deformation and final filling. Also, the processed sample can divided into undeformed zone, small deformation zone, shear deformation zone and severe deformation zone according to the metal flow and mesh distortion. Different loading ways of the upper and lower punches lead to the deviation of deformation zone, and the sample has less deformation homogeneity along with the more velocity difference between the two punches. The most homogeneous deformation with maximum strain of 3.97 and deformation uniformity coefficient of 1.89 was obtained while the velocity ratio was 1: 1. In addition, the deformation behavior under different routes was investigated. It is found that the deformation is more homogeneous under 4 passes of route B compared with route A, having a 29 % reduction in deformation uniformity coefficient and a 14 % increase in shear deformation zone proportion.