(上海交通大学金属基复合材料国家重点实验室， 上海 200030)
摘 要: 用挤压铸造、挤压比仅为10∶1的挤压以及进一步的轧制成功地制备了具有高应变速率超塑性行为的β-SiC晶须增强LY12复合材料。该复合材料晶粒细小，约为2μm；在温度为803K和初始应变速率为1.1×10-1s-1时，延伸率达350％，应变速率敏感系数 m 值约为0.35；超塑性变形的主要机制是细小晶粒的晶界滑动，适当的微量液相有利于该复合材料的高应变速率超塑性。
关键字: 高应变速率超塑性 铝基复合材料 挤压铸造
（State Key Laboratory of Metal Matrix Composites, Shanghai JiaoTong University,Shanghai 200030, P. R. China）
Abstract:A β-SiC whisker reinforced LY12 aluminum composite expected to exhibit high strain rate superplasticity has been successfully fabricated by squeeze casting and rolling after extrusion with a low extrusion ratio of 10∶1. The as-processed composite has a fine grain size of about 2μm, and exhibits a maximum total elongation of 350% and a strain rate sensitivity of about 0.35 at the initial strain rate of 1.1×10-1s-1 at 803 K. The dominant process of superplastic deformation is fine grain boundary sliding, and an appropriately small amount of liquid phase can enhance the high strain rate superplasticity of the composite.
Key words: high strain rate superplasticity aluminum matrix composites squeeze casting
