中文摘要：

采用原位反应近液相线铸造方法制备Al2O3P/Al-Cu复合材料,对其进行二次加热,研究晶粒的形貌演变和长大规律。用光学显微镜观察组织结构,应用Image Pro Plus软件测量并统计出平均晶粒尺寸及合金液相体积分数,并与理论计算数值进行比较。结果表明,在590℃保温10～60 min后,不含Al2O3颗粒的Al-6.8%Cu基体合金平均晶粒尺寸为89～132μm,液相体积分数为14%～26.8%,而3.6 wt%Al2O3P/Al-6.8%Cu复合材料的平均晶粒尺寸为73-107μm,液相体积分数为11.6%～20.9%。说明Al2O3颗粒在合金的二次加热过程中对晶粒长大行为及液相体积分数的增长均有明显的抑制作用,从而为优化半固态组织提供了一种新思路。

英文摘要：

The semi-solid Al2O3P/Al-Cu alloys cast with in-situ near-liquidus casting technology were reheated,and its microstructural evolution and grain growth mechanism were studied by means of optical microscope.The grain sizes and the volume fraction of liquid were measured using Image Pro Plus,and compared with theoretical calculation.The results indicate that under the combination of reheating temperature 590℃ and holding time 10～60 min,with no Al2O3 particles the Al-6.8%Cu matrix alloy has average grain size of 89～132 μm and liquid volume fraction 14%～26.8%,while 3.6 wt%Al2O3P/Al-6.8%Cu composite has average grain size of 73～107 μm and liquid volume fraction of 11.6% ~ 20.9%.The in-situ Al2O3 particle can control the grain sizes and the volume fraction of liquid growth evidently during reheating.Thus,the conclusion will offer one kind of new mentality for optimizing semi-solid microstructure.