A Novel Grain Refinement Design to Inhibit Liquation Cracking in Laser Cladding Non-Weldable Nickel-Based Alloy

The liquation cracking is easily induced in the heat-affected zone during laser cladding repairing the non weldable nickel-based superalloy, and there are currently no effective solutions. A novel grain refinement design strategy is proposed for laser cladding repairing non weldable superalloy. In the new strategy, static recrystallization, simulated by the heat from the molten pool, occurs in the plastic deformation region of the base metal pretreated via mechanical shot peening in the heating process of laser cladding. As a result, the coarse columnar crystal structure converts into fine equiaxed crystal structure in the heat-affected zone. The evolution behaviors of liquid film and recrystallization were studied via in-situ observation, and sound laser cladding layers were obtained.