Effect of heat input on heat affected zone cracking in laser welded ATI Allvac 718Plus superalloy

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 454; pp. 389 - 397
• Main Authors: Idowu, O.A., Ojo, O.A., Chaturvedi, M.C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 25-04-2007; Elsevier
• Subjects: Applied sciences; Exact sciences and technology; Fractures; HAZ cracking; Joining, thermal cutting: metallurgical aspects; Liquid film migration; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Superalloys; Welding; HAZ cracking; Welding; Superalloys; Liquid film migration; Cooling; Cracking; Laser welding; Grain boundary; Superalloy; Stress relaxation; Transition metal alloy; Stress effects; Heat affected zone; Weld zone; Liquid metal embrittlement; Nickel alloy
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2006.11.054

The heat affected zones (HAZs) of low and high heat input laser welds of a newly developed superalloy, ATI Allvac 718Plus, were studied. Low heat input welds suffered significant HAZ grain boundary liquation cracking, while no cracking was observed in spite of a more extensive HAZ intergranular liquation in the higher heat input welds. Combination of lower welding stresses generated during cooling, and relaxation of these stresses by thick intergranular liquid were suggested to be the factors that contributed to the absence of cracking in the high heat input welds. Further, healing of some of the HAZ cracks in lower heat input welds by fusion zone interdendritic liquid occurred through liquid backfilling.