Effect of Zener-Hollomon Parameter on Microstructure and Mechanical Properties of Copper Subjected to Friction Stir Welding

• 来源期刊: 金属学报（英文版）
• 年，卷（期）: 2020,（2）
• 页码范围: 319-326
• 页数: 8页
• 语种: 英文

摘要

In this work,the influence of the Zener-Hollomon (Z) parameter on the microstructure and mechanical properties of copper subjected to friction stir welding (FSW) was investigated.Liquid N2 cooling was conducted to control the cooling rate after the FSW.The obtained results demonstrate that the Z parameter was dependent on the tool rotation rate during the FSW,i.e.,a higher tool rotating rate resulted in a lower Z parameter.The grain size in the stir zone decreased with the increase in the Z parameter.The relationship between the yield strength and the Z parameter is established as σ0.2 =σ0 + kZn.This relationship exhibited two different plots under the conditions of air cooling and liquid N2 cooling.Even at a similar Z parameter,a significant yield strength difference occurred because massive dislocations,which were caused by the prevention of the post-annealing effect,were maintained in the stir zone.This study suggests that the influence of the post-annealing effect should not be neglected when analyzing the relationship between the Z parameter,microstructure,and mechanical properties.