The research on the geometrical characteristics and microstructure of the cladding track of DZ125L Nickel-based alloy deposited by laser metal direct deposition

Abstract This study investigates how variations in laser power, scanning speed, defocusing amount, and powder feeding impact the geometrical characteristics and microstructure of DZ125L nickel-based superalloy. The results show that the weld pool size increases with the rise of laser power, but higher laser power will increase the tendency of hot crack defects. With the increase of positive defocusing, the melting height and depth decrease, but the melting width rises first, then decreases and increases finally. The increase in scanning speed leads to the reduction in melting width and height, while the effect on melting depth is small. With the increase of powder feeding amount, the melting height and depth increase, while the melting width decreases, but too much powder feeding amount leads to some powder being difficult to melt. Increasing laser power or decreasing positive defocusing will lead to a rise in the size and proportion of cylindrical crystals in the molten pool. Increasing scanning speed and powder feeding amount will let the crystal direction of columnar crystal change from <001> to <101>.