摘要
通过疲劳试验机/扫描电镜的原位观察、以及扫描电镜/图像分析软件的定量分析,研究AZ31镁合金铸轧板材热变形过程中的空洞演化行为。结果表明:镁合金板材热变形过程中,空洞首先在晶界尤其是在三叉交界处形核,随后不断长大和聚合,导致材料断裂;空洞的长大具有方向选择性,与拉伸轴方向垂直的空洞容易长大。空洞长大机制的理论模型计算与试验结果对照表明:孔径小于2μm小空洞的圆度系数接近1,其主要长大机制为晶界扩散;孔径大于2μm大空洞的圆度系数和取向角均比较分散,其主要长大机制是塑性变形。
The cavity evolution behavior of twin-roll-cast AZ31 magnesium alloy sheet during hot deformation was investigated by in-situ SEM observation on the fatigue testing machine, and the characteristics of cavity were quantitative measured using graphical analysis software. The results show that the cavity nucleates while the twin-roll-cast AZ31 alloy sheet deforms, and the cavity starts on the tri-grain boundary. The continuously growth and coalescence of the cavities induce the material fracture. The cavities grow directionally and prefer to grow along axis perpendicular to the loading axis. The comparison between the theory analysis and experimental results shows that the shape of the cavity with diameter less than 2 μm is nearly spherical, and the main cavity growth mechanisms is diffusion. In contrast, the cavities with diameter larger than 2 μm tend to be elongated with the long axis parallel to the loading axis, the main cavity growth mechanisms is plasticity deformation.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2009年第5期785-792,共8页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目(50675115)
河南省科技攻关基金资助项目(072102340010)
关键词
AZ31镁合金
铸轧板材
空洞
扩散
塑性变形
AZ31 magnesium alloy
twin-roll-cast sheets
cavity
diffusion
plasticity deformation
