基体预热对激光沉积修复GH4169/K424合金开裂倾向的影响

During the deposition repairing process, components made of the highly crack-sensitive K424 nickel-based superalloy are prone to cracking. This study utilized the low-crack-sensitive alloy GH4169 to repair the K424 alloy and investigated the effect of substrate preheating on the cracking tendency of the GH4169/K424 alloy repaired by laser deposition. Numerical simulations of the repair process were conducted to examine the role of thermal and stress field evolution in crack formation. The simulation results indicate that preheating the substrate effectively reduces stress, with the most significant stress reduction occurring in the direction parallel to the laser scanning, where compressive stress decreased by 10.5% and tensile stress by 26.7%. Experimental validation demonstrated the inhibitory effect of preheating on the cracking tendency of the GH4169/K424 alloy repaired by laser deposition. Preheating the substrate to 300 ℃ significantly reduced the probability of crack formation, resulting in repaired K424 superalloy specimens with only minor cracks.