循环变形提高SiC纤维增强铝基复合材料强度及塑性 I.实验现象

CYCLE LOADING INCREASING THE STRENGTH AND PLASTICITY OF SiC FIBER REINFORCED ALUMINUM COMPOSITES I. Experimental Phenomenon

对ＳｉＣ纤维增强铝基复合材料经不同周次循环变形载荷后强度与塑性的测试表明．循环变形可使其强度、塑性均有所提高．经循环变形载荷作用１０周次、抗拉强度提高２０％；作用１００周次．强度提高３０％．塑性也有类似的变化．这一现象与传统疲劳损伤理论不一致．通过对基体材料、ＳｉＣ纤维体以及复合材料板的各自独立循环变形实验可知、这一现象同循环变形过程中纤维与基体的界面结合强度适度降低有关，这种降低有助于复合材料的强度与塑性的配合．

It was found that the strength and plasticity of SiC fiber reinforced composites can be increased by a certain cycle fatigue loading. The tensile strength was increased by 20% after 10 cycles fatigue loading and by 30% after 100 cycles loading. The plasticity showed the similar phenomenon. This phenomenon contradicts traditional fatigue and damage theory. Through a series of specially designed experiments, it can be concluded that the phenomenon does not result from cycling hardening of aluminum matrix, fiber reinforcement and the composite itself, but from the strength change of the interface between the matrix and fiber. The fatigue makes the interfacial strength decrease to an appropriate level, which is favorable to combination of the strength and plasticity of the composite.