低温退火加工硬化Al-10% Mg合金的显微组织特点和力学行为

Microstructural Characteristics and Mechanical Behavior of Work-Hardened Al-10wt% Mg Alloy Subjected to Low Temperature Annealing

摘要:

研究了冷轧减薄率为75%的Al-10% Mg（质量分数）合金在75~150 ℃下退火的显微组织特点和力学行为。轧制态和退火态Al-10% Mg合金的特征是晶粒细长，位错密度高，Al₃Mg₂相含量极低，且无弥散分布的Al₃Mg₂相。随着退火温度的升高，细长晶粒的宽度增加，位错密度减小。在75~150 ℃退火后，相比于轧制态合金，其屈服强度降低8%~33%，极限抗拉伸强度降低1%~12%，延伸率增加16%~83%。此外，分析了各种强化机制对屈服强度的贡献，以及原有位错和Mg溶质对塑性的贡献。

关键词:铝镁合金;冷轧;退火;强度;韧性

Abstract:

The Al-10wt% Mg alloy was cold-rolled with the thickness reduction ratio of 75% followed by annealing at 75~150 °C, and its microstructure characteristics and mechanical behavior were investigated. The as-rolled and annealed Al-10wt% Mg alloys are characterized by elongated ultra-fine grains, high density of dislocations, a very small amount of Al₃Mg₂ phase, and no dispersed distribution of Al₃Mg₂ phase. With increasing the annealing temperature, the width of elongated ultra-fine grains is increased and the dislocation density is decreased. After annealing at 75~150 °C, compared with those of as-rolled alloys, the yield strength of annealed alloys is decreased by 8%~33%, the ultimate tensile strength is decreased by 1%~12%, and the elongation is increased by 16%~83%. The contributions of various strengthening mechanisms to yield strength and the contributions of preexisting dislocations and Mg solute to ductility were analyzed and discussed.

Key words:Al-Mg alloys;cold rolling;annealing;strength;ductility