摘要
在温度450~520℃和1.67×10^(-3)~1.00×10^(-1)s^(-1)。初始应变速率条件下对Al-Mg-Sc-Zr合金冷轧板材进行拉伸实验,研究该合金的超塑性流变行为,探讨其超塑性变形机理。结果表明:随着变形温度的升高,伸长率先增加后减小,在500℃和初始应变速率6.67×10^(-3)s^(-1)条件下获得的最大伸长率为740%。合金的应变速率敏感因子为0.40,激活能为101 kJ/mol;在超塑性变形过程中,合金组织发生明显的动态再结晶,使原始纤维状晶粒等轴化;Al_3(Sc,Zr)粒子可有效钉扎晶界,抑制晶粒长大;超塑性变形过程的主要变形机制为晶界滑移,协调机制为晶界扩散控制的位错蠕变。
Abstract： The tensile tests for cold-rolled Al-Mg-Sc-Zr alloy were conducted at temperature of 450-500℃ and initial strain rate of 1.67 × 10-3-1.00×10-1 s-1. The flow behavior and deformation mechanism were investigated. The results show that the elongation changes as a parabola with the deformation temperature increasing, and the maximum elongation of 740% is achieved at 500℃ and 6.67× 10-3 s-1. The strain rate sensitivity is 0.40, and the activation energy is 101 kJ/mol. The obvious dynamic recrystallization （DRX） is observed, which can transfer the grain from original fibrous structure to equiaxed microstmcture. The A13（Sc,Zr） particles pin effectively at grain boundaries to resist grain growth. The grain boundary sliding is the dominant deformation mechanism during the superplastic deformation, the dislocation creep controlled by grain boundary diffusion is the main accommodation mechanism.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2016年第2期280-287,共8页
The Chinese Journal of Nonferrous Metals
基金
国家重点基础研究发展计划资助项目(2012CB619503)~~
