氧化铝短纤维增强铝基复合材料的蠕变破坏行为

研究了挤压铸造Al₂O₃短纤维增强铝基复合材料在350℃恒应力条件下的蠕变行为。蠕变试验过程中采用中断实验的方法对复合材料的显微组织进行观察,发现复合材料在蠕变过程中纤维发生断裂,弱界面发生破坏以及基体合金在应力作用下发生变形。根据复合材料在蠕变三个阶段中显微组织的变化情况,对其宏观蠕变行为进行了分析,认为位错在复合材料中滑移和攀移控制整个蠕变过程,并提出了短纤维增强金属基复合材料的蠕变断裂机理,合理地解释了复合材料的蠕变过程。 

CREEP BEHAVIOR OF SHORT ALUMINA FIBER REINFORCED Al BASED COMPOSITE

The constant stress creep behavior at 350 ℃ was investigated for Al2O3 fiber reinforced Al based composite fabricated by squeeze casting. During the interrupted creep process, the variations of microstructure were observed by means of SEM. The fracture of fibers, the debonding of fiber and matrix, and the deformation of matrix were found in creep of composite materials. On the basis of the changes of microstructure in three phases of creep, the creep behavior of the composite was analyzed. It is suggested that the glide and climb of dislocation around fibers contribute to creep of the composite.The authors propound a rupture mechanism of short fiber reinforced MMCs, which succeeds in interpreting the three stages of creep for composites.