铝基复合材料超塑性变形机制

Superplastic Deformation Mechanisms of Aluminum Matrix Composites

在对比研究25vol％SiCw(d×1＝0.8×12μm)／LY12和12vol％SiCp(d＝10μm）／LY12复合材料的超塑性变形特性与微结构的基础上探讨了铝基复合材料的超塑性变形机制。研究表明，陶瓷增强物对铝基复合材料的起塑性有非常大的影响。其超塑性变形的主要机制是基体晶粒的晶界滑动，增强物尺寸、晶粒尺寸小的铝基复合材料，晶界和界面上的适量液相是调节晶界滑动的主要机制；增强物尺寸、晶粒尺寸大的铝基复合材料，除了液相，动态回复也是调节晶界滑动的重要机制。

In this paper, the superplastic de formation mechanisms of aluminum matrix composites have been investigated on the base of a comparison of superplastic characteristics and microstructures of 25vol% SiCw(d×1=0.8×12μm)/LY12 and 12vol %SiCp(d=10μm) /LY12 composites. The results show that the ceramic reinforcements have very great influences on the superplasticity of aluminum matrix composites. The dominant superplastic mechanism of aluminum matrix composites is grain boundary sliding.For the composite having a fine reinforcement and grain, the accommodation mechanism for grain boundary sliding is primarily the appropriate amount of liquid phase presented at grain boundaries and interfaces, but for the composite having a large rein forcement and grain, dynamic recovery is also an important accommodation mechanism in addition to the liquid phase. (note: w, d, 1, p represent whisker, diameter, length and particulate, respectively)