基于断口观测的2A12铝合金微动疲劳损伤研究

The fretting fatigue damage research based on fracture observation of 2A12 aluminum alloy

在航空方面,微动损伤会导致飞机产生隐蔽的多裂纹,甚至造成灾难性事故的发生。基于断口的微动疲劳损伤研究非常重要,能从本质上了解裂纹成核及扩展机理。为了更好地理解2A12铝合金的微动疲劳微观损伤机制,利用专用设备对微动疲劳断口进行观测及分析,结果表明:裂纹大多由小坑处产生,坑深并不是裂纹成核的主要因素;氧化磨屑渗入到裂纹中达10多微米,使裂纹在常规检查中很难被发现;裂纹成核于试件的表面或次表面,为穿晶扩展;微动疲劳会导致多裂纹的产生,但只有一两条裂纹成为主导裂纹。

Fretting fatigue can lead to the formation of hidden multiple cracks for the aircraft on aviation, and result in the occurrence of disastrous accident. The fretting fatigue damage research based on fracture observation is very important,which can crack initiation behavior and propagation mechanism. In order to understand microcosmic damage mechanism better, the fretting fatigue fracture was observed and analysed based on special equipments. The results show that the cracks generate from the pitting mostly and the pit depth is not the major factor for crack intiation. The oxide debris permeate into the cracks for more than 10 microns, which make the crack is hard to find in the routine inspection. The crack nucleate from the surface or the sub-surface of the specimen, and is transgranular extension. The fretting fatigue will lead to many cracks, but only one or two cracks become dominant crack.