Fatigue fracture behavior of 5A06 aluminum alloy and its welded joint
Fatigue fracture behavior of 5A06 aluminum alloy and its welded joint
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发表时间：
2013
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通讯作者：
Li Yong-lian
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作者：
Li Yong-lian
对5A06铝合金及其焊接接头的疲劳断裂行为进行了研究，采用疲劳试验、金相显微镜和扫描电镜等手段，对5A06铝合金及其焊接接头的疲劳性能、微观组织、疲劳裂纹扩展特征和疲劳断口进行了分析。横向连接接头（LJ）和纵向交叉接头（LCJ）的疲劳强度分别为99.97、70.96、57.48、48.20和41.80 MPa，母材的疲劳裂纹萌生位置在最小截面，BJ和TJ的裂纹萌生位置在焊趾，裂纹沿着HAZ扩展，LJ裂纹萌生于角焊焊脚，LCJ裂纹萌生于热影响区，微观裂纹沿晶和穿晶扩展，疲劳宏观断口呈深灰色纤维状断口，具有一定的塑性，微观断口由准解理、球形孔洞、疲劳条纹和韧窝组成，并观察到大量的二次裂纹。
Fatigue testing fracture behavior was researched on 5A06 antirust aluminum alloy and its welded joints.The fatigue properties,microstructure,fatigue crack propagation character and fatigue fracture were investigated by fatigue test,optical microscopy(OM) and scanning electronic microscopy(SEM).Under cycle times of 2×106,the fatigue strengths of base metal(BM),butt joint(BJ),transverse cross joint(TJ),lateral connection joint(LJ) and longitudinal cross joint(LCJ) are 99.97,70.96,57.48,48.20 and 41.80 MPa,respectively.The fatigue crack initiation site is in the smallest section for base metal,the crack initiation is in the weld toe and the crack propagates along the HAZ for the BJ and TJ,the crack initiation is in the fillet weld leg for the LJ,the crack initiation is in HAZ for the LCJ,the micro-crack propagates for transgranular and intergranular.The fatigue macro-fracture shows a dark gray fibrous fracture patterns and has some plasticity,the micro-fracture surface consists of quasi-cleavage patterns,spherical hole,fatigue striation and dimple,and numerous secondary cracks are observed.