The tensile properties under room temperature,and under liquid nitrogen temperature,and the distributing
of micro-hardness,and the results with digital speckle correlation method were compared between 2219 aluminum
alloy joints with single-layer welding and single-sided double-layer welding process. The comparison shows that the
tensile strength,the elongation rate and the micro-hardness of the joint with single-sided double-layer welding is obviously
better than the single-layer welding joint. This different is caused by the bigger heat input of single-layer welding
than the double in one time. The materials in the single-layer welding joint was more badly influenced by welding heat
input,and the height and figure of weld reinforcement on back side of joint is difficult to control