In situ Passive Infrared Thermography Application for the Assessment of Localized Mechanical Properties of Tungsten Inert Gas-Welded Inconel 625 Alloys

Traditional evaluation of weld joint mechanical properties by destructive testing shows the limitations of these methods, including equipment limitations, high materials/testing cost, and challenging repeatability. This work presents an experimental approach for utilizing passive infrared thermography and tensile testing to evaluate the correlation between thermal and localized TIG-welded Inconel 625 joints\u27 mechanical properties. The results show that different areas of interest deform differently during the tensile test. The dog-bone shaped TIG-welded samples were divided into five regions of interest on both sides of the weldment, of which two are repetitive on both sides of the sample representing Inconel 625 base metal alloy, heat-affected zones, and weld beads. The temperature change rate in these three regions varied from 0.17 to 0.67°C per minute as the tensile test progresses. The fractography analysis showed that the failure occurred within the weld beads, even though the highest temperature was observed in the heat-affected zones, suggesting higher strength in the heat-affected zones. The improvement mechanism introduced in this work utilizes thermography visualization to predict weld failure as nonlinear elongations are observed across different stages during the tensile tests