SiC颗粒增强铝基复合材料细观损伤的温度效应

Temperature Effect Research on Meso-Damage for Particle Reinforced Aluminum Matrix Composites

SiC颗粒增强铝基复合材料的宏观力学行为与其微观损伤机理密切相关,随温度的升高,材料力学性能明显下降,SiCp/A356复合材料表现出不同的细观损伤机理.文中对真空双搅拌方法制备的质量分数为20%的SiC颗粒增强铝基复合材料在室温和高温下的细观损伤机制进行了研究,在试样断口上,通过扫描电镜观察到了不同的裂纹萌生和扩展机制,根据不同温度下表现出的不同失效方法,归纳出了复合材料细观损伤的温度效应曲线.研究表明,在室温下复合材料的裂纹萌生以基体撕裂和颗粒断裂为主,高温下其裂纹萌生机制以颗粒脱离和基体撕裂为主.

Macro-mechanical properties were closely related with the meso-damage mechanism of SiC particle reinforced aluminum matrix composites （SiCp/A356）. As the temperature increased, the mechanical properties of the composites decreased significantly, and the meso-damage mechanism of the composites became different at various temperatures. The temperature effect on meso-damage for 20vol% SiCp/A356 was studied, and SiCp/A356 was fabricated by means of the double stir casting method under vacuum in this paper. The diverse crack initiation and propagation behaviors were observed by using an S-250M K3 scanning electron microscope （SEM） on the fractured surfaces. According to the different failure mechanism at various temperatures, the relation curve between mesodemage behavior and temperature was presented. It can be concluded that the crack initiation mechanism of the composites at room temperature was mainly tear of the matrix and fracture of SiC particles, while the mechanism of the composites at high temperatures was SiC particle debonding from the matrix and tear of the matrix.