(1.哈尔滨工业大学 材料科学与工程学院， 哈尔滨 150001;
2.日本千叶工业大学 金属工学科;
3.日本千叶工业大学 附属材料解析中心)
摘 要: 选用5.0和0.15μm两种粒径的Al2O3颗粒，制备了Al2O3体积分数为40%的铝基复合材料。利用透射电镜对两种复合材料拉伸前后的组织进行观察，结果表明：5μm尖角形Al2O3颗粒增强复合材料的铸态组织中存在高密度的位错，这主要是由于热错配应力引起的；0.15μm椭球形Al2O0颗粒增强复合材料的铸态组织中几乎观察不到位错，这与颗粒细小且为等轴状、分布弥散、界面附近应力分布均匀等因素有关。对拉伸断口附近显微组织的观察表明，前者基体中位错进一步增殖，后者则存在明显的位错环。室温拉伸结果表明亚微米Al2O3p/Al复合材料中的这种微观组织有利于材料强度和塑性的提高。
关键字: 金属基复合材料；显微组织；力学性能
microstructure and properties of
Al2O3p/Al composites
（1.Department of Materials Science and Technology, Harbin Institute of
Technology, Harbin 150001, China;
2.Department of Metallurgical Engineering, Chiba Institute of
Technology, Japan;
3.Analysis Center of Materials, Chiba Institute of
Technology, Japan）
Abstract:Aluminum matrix composites with alumina particles of 40%(volume fraction) were fabricated using 5.0μm and 0.15μm Al2O3 particles respectively. The microstructure of the two kinds of composites before and after tension was investigated with transmission electron microscope (TEM). It was found that there was a high dislocation density in the as-cast composite reinforced by 5?μm sharp-angle-shaped Al2O3 particle s, due to the thermal mismatch stress. In contrast, little dislocation was observed in the as-cast composite reinforced by 0.15?μm spherical Al2O3 particles, which could be attributed to the following factors, such as the dispersion of the equiaxed fine particles, uniform distribution of the stress near the interfaces, etc. The microstructural observation near the fracture indicated that dislocations increased in the matrix of the former composite, while obvious dislocation loops were found in the latter. The room temperature tensile test confirmed that such microstructure in the sub-micro Al2O3p/Al composites was beneficial to an increase in their strength and ductility.
Key words: metal matrix composites; microstructure; mechanical properties
