中文摘要：

采用原位反应近液相线铸造方法制备含有少量原位仙03颗粒的Al—Cu基复合材料，利用光学显微镜观察复合材料的铸态组织，并通过透射电镜观察复合材料中的原位Al2O3颗粒的分布与形貌，研究原位颗粒对近液相线铸造Al-Cu合金铸态组织形成机制的影响．结果发现：原位Al2O3颗粒比较均匀地分布于基体合金中，尺寸分布于1μm范围内，形貌呈多边形．随着原位Al2O3颗粒含量的增加，复合材料的铸态组织逐渐被细化和均匀化；当原位Al2O3颗粒的质量分数达到5．396时，获得均匀细小的蔷薇状组织．

英文摘要：

Microstructures of in-situ reactive near-liquidus cast Al2O3/Al-Cu matrix composites were observed by optical microscope, and transmission electron microscope was used to examine the distribution and morphology of in-situ Al2O3 particles in the Al-Cu alloy matrix. The effect of in-situ Al2O3 particles on the formation mechanism of mierostructure of the near-liquidus east Al-Cu alloy was analyzed. It is shown that as-cast microstructures of the in-situ processed composites have a relatively uniform distribution of Al2O3 particles within 1 μm in average size and the Al2O3 particles have polygon morphology. The rose-flowered structure gradually fines and homogenizes with increasing the mass fraction of in-situ Al2O3 particles; while the mass fraction of Al2O3 particles is up to 5.3 %, a fined and homogenized rose-flowered structure is obtained.