A study of the processing and characterization of RSM optimized YSZ-Inconel625 wear-resistant TIG weld cladding

Abstract

The present investigation focuses on developing a wear-resistant Yttria Stabilized Zirconia (YSZ) reinforced Inconel-625 (IN625) based TIG weld composite cladding on the AISI 304 stainless steel substrate. TIG welding current, scanning speed, standoff distance and YSZ reinforcement % were the primary input process parameters for cladding deposition. For the optimization of process parameters, cladding was deposited at different parametric settings, and their microhardness and sliding wear resistance was calculated as the output responses, according to Box Behnken Design (BBD) under Response Surface Methodology (RSM). Feedstock powders, developed claddings and worn samples were examined to study their surface morphology, microstructure, element composition and different phases using the SEM, Optical Microscopy, EDS, and XRD techniques. The result revealed that welding current and scanning speed are the most significant factors which govern the mechanical and tribological properties of cladding. The cladding was deposited at an optimized welding current 70 A, scanning speed of 192 mm min−1, standoff distance of 2 mm, and 25 wt.% YSZ reinforcement concentration revealed the fine and dense microstructure, resulting in maximum hardness and minimum wear. The microstructure was observed to be columnar dendrites, which grew epitaxially from the substrate. The addition of YSZ particles into the IN625 matrix resulted in the formation of Cr2O3 and ZrO2 stable oxides along with γ-Ni (FCC) phases. The wear test showed that the weight loss in claddings was mainly due to abrasive wear.