不同应力水平下5A06铝合金的疲劳断口研究  

Fatigue Fractography of 5A06 Aluminum Alloy Under Different Stresses

作　　者：刘乐乐[1] 姜锋[1] 汪莹[1] 李致良 

机构地区：[1]中南大学材料科学与工程学院,长沙410083

出　　处：《宇航材料工艺》2015年第5期70-74,共5页Aerospace Materials & Technology

摘　　要：通过采用金相显微镜,扫描电镜和能谱分析研究了5A06铝合金高周疲劳断口的微观特征。研究结果表明:该合金在疲劳极限附近发生疲劳断裂时,裂纹主要萌生于杂质粒子与基体的界面结合处,较高应力水平下疲劳裂纹的萌生呈现多源性,并且裂纹主要起源于杂质粒子自身的开裂。随着应力水平的提高,裂纹的偏转路径更加复杂,疲劳辉纹间距不断增大,断口中疲劳裂纹扩展区所占比例减少。疲劳裂纹扩展的初期,疲劳微裂纹的偏转主要取决于相邻晶粒间有利滑移面的方向。The high cycle fatigue fractography of 5A06 aluminum alloy was investigated by means of optical mi- croscopy（OM）, scanning electron microscopy （SEM） and energy dispersive spectrometer （EDS）. The results show that the fatigue cracks mainly initiate at the interface between impurities and matrix when the loading stress is near the fatigue limit. Multi-source fatigue cracks appear with the increase of the stress and the cracks originate mainly from the broken impurities. The crack deflection path becomes more complex, the fatigue striation increases and the fatigue expansion area becomes smaller with the stress increasing. The direction between adjacent grain favored slip planes determines the deflection of the micro-crack in the early stage of the fatigue crack propagation.

关 键 词：5A06铝合金 高周疲劳 裂纹偏转 疲劳辉纹 

分 类 号：TG111.8[金属学及工艺—物理冶金] TG146.2[金属学及工艺—金属学]