中文摘要：

采用原位反应近液相线铸造法制备4.4%TiCp/7075Al基复合材料,在600℃保温10～60 min,水淬固定其半固态组织,研究半固态二次加热过程中合金的晶粒长大规律,并与采用同样方法制备的7075基体合金进行对比分析。结果表明,4.4%TiCp/7075Al基复合材料的晶粒粗化速率常数为118.96μm3/s,远小于7075基体合金的晶粒粗化速率常数311.7μm3/s,晶粒长大速率明显减慢。分析其原因,由于原位TiC颗粒的生成,使得4.4%TiCp/7075Al基复合材料的晶粒长大激活能增加约50%,从而对二次加热过程中晶粒迅速长大的行为起到了显著的抑制作用。

英文摘要：

4.4% TiCp /7075 Al composite was prepared by in-situ reactive near-liquidus casting,and 7075 Al alloy and the composite were re-heated isothermally at 600 ℃,which is in the two-phase（liquid and solid） region（477—635 ℃） of near-liquidus casting 7075 alloy,for 10—60 min,then quenched in water.The effect of in-situ TiC particles on microstructure of the 4.4% TiCp /7075 Al composite was examined and it was compared with that of the 7075 alloy.The result shows that the coarsening velocity constant of grain for 4.4% TiCp /7075 Al composite is 118.96 μm3 /s,which is more less than 311.7 μm3 / s of 7075 alloy.The activation energy of grain growth for the in-situ 4.4% TiCp /7075 Al composite is about 1.5 times of that for the 7075 alloy,which is responsible for the inhibition of grain growth of 4.4% TiCp /7075 Al composite.