A low-cycle fatigue life prediction model for Alloy625 arc wire welding repairs of gas turbine blades

Wire arc deposition is an interesting manufacturing technique for producing metallic parts made of Ni-based alloys, for cladding and for repairs in turbine components. This technique, when compared to power bed fusion processes, allows to obtain parts with a limited porosity. In this paper, a wide experimental campaign on the Alloy625 wire arc deposited alloy was carried out to characterize its mechanical behavior under low cycle fatigue conditions. Specific specimen geometries were implemented to reproduce the welded Alloy625 mechanical behavior as solid material or thick repairs. A crack propagation model based on the effective value of the J-integral range is proposed to simulate the propagation of a potential crack originated from a welding defect. The work aims to provide a robust methodology to approach the damage tolerance design of solid and repaired parts obtained by wire arc deposition.