Fatigue property comparison of TIG welded joints of magnesium alloy and aluminum alloy

The fatigue properties of the TIG welded joints of both AZ31B magnesium alloy and 5A06 aluminum alloy were investigated.The four types of welded joints were used in fatigue tests,such as butt joints,transverse cross joints,fillet joints and lateral connecting joints.The fatigue strengths at 2×10~6 cycles of the four welded joints of AZ31B magnesium alloy are 39.0 MPa,24.4 MPa,32.1 MPa and 24.2 MPa,which are 55.0%,42.2%,78.0% and 50.2% of that of 5A06 aluminum alloy,respectively.The fatigue strength levels at slope m=3 of the aluminum alloy's welded joints are mostly higher than the FAT recommended by the International Institute of Welding (IIW),while those of the magnesium alloy's welded joints are all lower than the FAT.It is indicated that the FAT of magnesium alloy's welded joints should be established as early as possible in order to be applied in the design of magnesium alloy's welded structures.     

Fatigue Crack Propagation Behavior of as-Extruded AZ31B Mg Alloy Welded Joint

对AZ31B 镁合金焊接接头和热影响区的疲劳裂纹扩展行为进行研究,分析了焊接接头[L-T(W)]和热影响区的紧凑拉伸试验[C(T)],其中热影响区的C(T)试验包括焊缝平行于挤压方向[T-L(H)] 和垂直于挤压方向 [L-T(H)]两种。结果表明:对于L-T(W) 试样,裂纹沿挤压方向扩展,裂纹扩展经历先快后慢的扩展过程;T-L(H) 试样裂纹平行于缺口方向扩展,L-T(H)试样裂纹为平行于缺口方向和与缺口成一定角度两种扩展方向,裂纹扩展经历先慢后快的扩展过程。裂纹尖端扩展为穿晶和沿晶的混合模式,疲劳断口为准解理特征的脆性断口。     

AZ31B镁合金焊接接头的疲劳裂纹扩展行为(英文)

对AZ31B 镁合金焊接接头和热影响区的疲劳裂纹扩展行为进行研究,分析了焊接接头[L-T(W)]和热影响区的紧凑拉伸试验[C(T)],其中热影响区的C(T)试验包括焊缝平行于挤压方向[T-L(H)] 和垂直于挤压方向 [L-T(H)]两种。结果表明:对于L-T(W) 试样,裂纹沿挤压方向扩展,裂纹扩展经历先快后慢的扩展过程;T-L(H) 试样裂纹平行于缺口方向扩展,L-T(H)试样裂纹为平行于缺口方向和与缺口成一定角度两种扩展方向,裂纹扩展经历先慢后快的扩展过程。裂纹尖端扩展为穿晶和沿晶的混合模式,疲劳断口为准解理特征的脆性断口。