(西安交通大学 机械工程学院， 西安 710049)
摘 要: 研究了应力三轴度温度、应变速率对颗粒增强金属基复合材料(PRMMCs)断裂应变的影响。结果显示， 高温下PRMMCs的断裂应变对应力三轴度非常敏感，断裂应变和应力三轴度的指数函数成反比关系。高温断裂应变值随应变速率的增加呈抛物线形式下降，而随温度的降低呈线性减小。断口分析显示，高温变形时，材料韧窝的直径随应力三轴度的增大而减小；室温拉伸应力三轴度与韧窝的大小无关。
关键字: 复合材料； 应力三轴度； 温度； 应变速率； 断裂应变
aluminum alloy matrix composites
（School of Mechanical Engineering, Xi′an Jiaotong University,
Xi′an 710049, P.R.China）
Abstract:A study is made to determine how the stress triaxiality, temperature and strain rate could influence the fracture strain of SiC particulate reinforced metal matrix composites (PRMMCs). The results show that, at high temperatures, the fracture strain value of the PRMMCs is highly sensitive to stress triaxiality and inversely proportional to the exponential function, the exponential function of the stress triaxiality; the fracture strain value of the composites decreases in parabolic pattern with the increment of strain rate and decreases in line shape with the dropping of forming temperature. The fractograph investigation indicates that, accompanying the increasing stress triaxiality, the diameter of dimple is reducing at elevated temperature, but the diameter is not sensitive to the stress triaxiality factor at room temperature.
Key words: composites； stress triaxiality； temperature； strain rate； fracture strain
