Browsing by Author "Rama Aravinth, K. V."

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    Effect of solutionizing and double ageing treatments on the microstructural characteristics and tensile properties of Inconel 718 welds
    (Elsevier, 2023-09-07) Devendranath Ramkumar, K.; Arvind, A. V.; Rama Aravinth, K. V.; Srivatson, E.; Ganguly, Supriyo
    Inconel 718 joints were fabricated using the pulsating direct current gas tungsten arc welding (PDCGTAW) and laser-arc hybrid welding (LAHW) techniques using Ni-Cr-Mo-rich filler. A cyclic post-weld heat treatment (PWHT) comprising 980°C/20 min./air cooling; followed by two-stage ageing 720°C/8 h/furnace cooling and 620°C/8 h/air cooling was performed on both joints. The liquation cracking was noticed on the heat-affected zone (HAZ) of the LAHW joints. Microstructural characteristics were assessed on the joints in both as-welded (ASW) and PWHT conditions. Regardless of the joints, the coarse Mo-rich segregates were noticed in the fusion zone (FZ) in the ASW conditions. On the contrary, the partial dissolution of MC, precipitation of δ-Ni3Nb needles and the coarsening of strengthening precipitates were observed on LAHW and PDCGTAW joints after subjecting to cyclic PWHT respectively. Tensile studies corroborated that there is a considerable enhancement in the tensile and 0.2% offset yield strengths of LAHW joints after being exposed to PWHT, despite the formation of HAZ liquation cracking.