中文摘要：

采用原位反应近液相线铸造方法制备4.4%TiCP/7075铝复合材料,在基体合金的液-固两相区间（477～635℃）的600℃分别保温10、20、40、60 min,水淬固定其半固态组织,应用Image Pro Plus软件测量平均晶粒尺寸,研究原位TiCP对二次加热组织的影响。结果表明,原位TiCP不仅使合金铸态组织直接转变为等轴晶组织,而且在二次加热过程中,对晶粒的长大行为具有明显的抑制作用。在相同的二次加热条件下,TiCP/7075铝复合材料的平均晶粒尺寸比7075基体合金减小了30～40μm,更适合于半固态触变成形。

英文摘要：

The 4.4%TiCP /7075 matrix composite was prepared by in-situ reactive near-liquidus casting.The sectioned specimens were heat-treated isothermally at 600℃ between the two-phase（liquid-solid） region（477~635℃） of the near-liquidus cast 7075 alloy for 10,20,40 and 60 min,then quenched in water.The grain size was measured using the software Image Pro Plus and the effect of in-situ TiCP on the reheating structure was analyzed.The result shows that the in-situ TiCP with fine and globular can not only keep near-liquidus cast 7075 alloy microstructure,but also control evidently grains growth by pinning effect during reheating.Dealing under the same condition,the grain sizes of TiCP/7075 matrix composites are 30～40 μm less than those of 7075 alloy,which is very suitable for thixoforming.