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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。
The in-situ reactive near-liquidus casting method was used to prepare a 4.4% TiCp / 7075Al matrix composite and then was held at 600 ℃ for 10 ~ 60 min. The semi-solid structure was fixed by water quenching. The grain length Large scale, and with the same method of preparation of 7075 matrix alloy comparative analysis. The results show that the grain coarsening rate constant of 4.4% TiCp / 7075Al matrix composite is 118.96μm3 / s which is much lower than that of 7075 matrix alloy. The rate of grain growth slows down remarkably. The reason for this is that the grain growth activation energy of 4.4% TiCp / 7075Al matrix composites increases by about 50% due to the formation of in-situ TiC particles, which leads to the rapid growth of grains during secondary heating Inhibition.