Property of spot weld of high strength magnesium alloy

Mg₉₆Zn₂Y₂ magnesium alloy sheet was resistance spot welded. The microstructure of joint was observed by scanning electron microscope. The effect of welding current on the nugget diameter and tensile shear load of joint was analyzed. The influence of microstructure on the property of joint was discussed. The nugget diameter and tensile shear load increased with the increase of welding current. The maximum shear strength of joint, approximately 142 MPa, was obtained. Fine mesh like second phase existed in the nugget zone, α-Mg grains were approximately 30 μm in diameter. The results reveal that the microstructure characteristics were the main reason for weakening of joining strength.