Characterization of Mechanical Behavior in Solution-Treated Micro Plasma Arc Welded Blanks of Inconel 625

This investigation aims to comprehensively understand the mechanicalproperties and deformation response of Inconel 625 micro plasma arc welded blanks(MPAWB) of 0.5 mm sheets, with specific attention to their formability. Thewelded blanks are solution heat treated at 1100 ºC with holding time of1 h for potential alterations in their forming behavior. The joint metallurgyof various zones, including the fusion zone (FZ), is assessed through advancedtechniques such as FESEM, TEM and XRD analysis. A micro hardness, uniaxial tensileand limiting dome height tests (LDH) have been carried out to evaluate themechanical properties of MPAWB and solution treated welded blank (STWB). Theanalysis reveals that the FZ of the MPAWB predominantly comprises of nickelγ-matrix along with diverse dendritic structures, alongside some secondaryphases like Laves phase, NbC, and TiC. After the ST, the dendritic structures in theFZ of MPAWB melt and recrystallize, creating a more uniform microstructure. Thedissolution of secondary phases in the STWB leads to a reduction in dislocationdensity compared to the MPAWB. Furthermore, the hardness of STWB decreases from269 ± 9 HV to 252 ± 6.75 HV, and a notableincrease in elongation by 12.4%, compared to the MPAWB. A significantimprovement in the LDH is observed for STWB, with a value of 14.89 mm,compared to 13.7 mm for the MPAWB. The forming limit diagrams of IN 625,MPAWB and STWB exhibit similar strain and thickness distributions along theuniaxial-to-biaxial strain path. Notably, symmetric strain and thicknessdistribution are detected on both sides of the pole for all the cases.