Effect of beam displacement on joint properties of laser welding of DD407/GH1140

Abstract:

Laser butt welding of DD407 and GH1140 commonly used for aeroengine blisk was conducted in this paper. The effects of beam displacement on mechanical properties, microstructure characteristics, and microhardness of laser joints were comprehensive analyzed. The results showed that the tensile strength of the joint reached 466.3MPa, which was NOT resulted from beam displacements, while determined by the performance of base metal GH1140. The morphology of joint cross section shaped like "wine-cup", and the microstructure of weld mainly consisted of columnar grains growth from both sides of weld and equiaxed grains in weld centre. The gradually increased distribution of micro-hardness along horizontal line located upper side of joint cross-section from base metal of GH1140, weld, to base metal of DD407 in different laser beam displacements was considered as the results from the solution strengthening of W and Co elements,the increased content of γ" strengthening phase, and the coarsened grains in weld.

Key words:beam displacement; laser welding; dissimilar materials; joint performance