声发射方法表征B4C/6061Al复合材料疲劳损伤机制

摘要

This paper discussed the fatigue behavior and associated acoustic emission response to reveal the fatigue damage evolution of the B4C particle reinforced 6061Al matrix composite.Tension-tension fatigue tests were conducted to obtain the fatigue behavior of B4C/6061Al.The hysteresis behavior was monitored under specific loading to study the fatigue damage mechanism of the composite.The fracture surface of B4C/6061Al was observed by scanning electron microscope.To gain insight into the fatigue failure mechanism,cyclic modulus and plastic dissipated energy were employed to characterize the fatigue behavior,and there was a linear relationship between the ratio of hysteresis energy to mean strain and fatigue stress.The monitored acoustic emission responses were in good agreement with the cyclic modulus and capable of describing the damage evolution of the composite under cyclic loading.%对B4C/6061Al复合材料在疲劳载荷作用下的声发射响应和动态弹性模量进行了研究,综合表征了复合材料的疲劳损伤与裂纹萌生机制.检测了B4C增强铝基复合材料在应力控制拉拉疲劳试验下的疲劳性能,通过建立模型分析复合材料的断裂机理并通过动态弹性模量声发射耦合方法分析B4C/6061Al复合材料在疲劳载荷作用下的疲劳损伤机制;同时使用扫描电镜观察复合材料断口形貌,分析其断裂行为;最终通过所建立的模型分析复合材料断裂机理,并通过动态弹性模量-声发射耦合分析B4C/6061Al复合材料在循环载荷下的疲劳损伤机制,建立复合材料塑性应变能、疲劳应变之间的线性关系.