中文摘要：

采用湿成型法成功制备了比重差别大的WO3颗粒（WO3p）和硼酸铝晶须（ABOw）混杂预制块,用挤压铸造法制备混杂铝基复合材料。混杂复合材料中含（原子分数）5%WO3p和20%ABOw,不同大小的WO3p尺寸分别为18和3μm。采用扫描电镜（SEM）和万能拉伸试验机对制备的混杂复合材料试样进行微观组织观察和拉伸性能测试。复合材料组织观察表明,WO3p和ABOw在基体中随机、均匀地分布,在高倍照片中可以观察到大尺寸WO3p存在裂纹,铝液不能渗入到裂纹中。力学性能研究结果表明,尺寸较小的颗粒增强的复合材料具有高的抗拉强度和断裂延伸率;含大尺寸WO3p的混杂复合材料的抗拉强度、屈服强度和断裂延伸率分别为266.8,197.3 MPa和1.16%,含小尺寸WO3p的混杂复合材料的抗拉强度、屈服强度和延伸率分别为290.3,180.5 MPa和1.37%。复合材料拉伸断口形貌观察表明,两种不同WO3p尺寸的混杂复合材料断裂机制有所不同,大颗粒增强复合材料中大颗粒发生断裂,裂纹穿过颗粒扩展,晶须与界面脱粘;小颗粒增强复合材料中小颗粒与基体界面脱粘以及晶须与界面脱粘,但晶须脱粘数量明显减少,晶须拔出数量增多。

英文摘要：

The hybrid preforms,containing WO3particles（ WO3p） and aluminum borate whiskers（ ABOw） with large difference in specific gravity,were fabricated by wet process. Then the hybrid aluminum matrix composites were fabricated by extrusion casting.There were 5% WO3 p and 20% ABOw（ atom fraction） in the hybrid composites,and the sizes of WO3 p were 18 and 3 μm,respectively. The microstructure was observed by scanning electron microscopy（ SEM） and the tensile property was tested by universal tensile testing machine. The results of microstructure observation showed that the reinforcements were distributed randomly and uniformly in the matrix. Cracks in bigger WO3 particles were observed by high magnified image,and the aluminum liquid could not infiltrate into the cracks. The results of tensile testing showed that the hybrid composites with smaller WO3 particle size had higher ultimate tensile strength and elongation than those of the composites with bigger WO3 particle size. The ultimate tensile strength,yield strength and elongation of hybrid composites with larger WO3 particles were 266. 8,197. 3 MPa and 1. 16%,respectively. Moreover,The ultimate tensile strength,yield strength and elongation of hybrid composite with smaller WO3 particles were 290. 3,180. 5 MPa and 1. 37%,respectively. The observation of fractured morphology showed that the fracture mechanism of hybrid composites with different WO3parti-cle sizes was different. For bigger particle reinforced composite,the WO3 particles fractured,then the cracks propagated across the particles and ABOw debonded from the interface between matrix and ABOw. For smaller particle reinforced composite,the particles and ABOw debonded from the interface between matrix and reinforcements. However,the debonded ABOw in smaller particle reinforced composite were less than those in bigger particle reinforced composite.