Effect of pre-welding heat treatments on welding a two-phase Ni3Al alloy

摘要: Abstract Autogenous gas-tungsten are welding was performed on a two-phase Ni 3 Al alloy. Plates mm thick were cut from cast ingot and subjected to three pre-welding heat treatments (PWHT), namely as-cast, annealed at 1100 °C for 23 h (HT1) HT1 plus 1120 °C/30 min/air cooled (HT2). The as-cast alloy characterized by dendrites with many eutectic cells located dendrite boundaries (DBs). destroyed HT1. However, HT2 made no further changes the microstructure. Analysis energy-dispersive X-ray spectroscopy (EDX) revealed that DBs of enriched Zr. Zr enrichment increased HT2. No crack visible unaided eye found in either fusion zone (FZ) or heat-affected (HAZ) due welding. FZ consisted columnar grains structure along boundaries. contained microcracks some Zr-rich phases. Micro-solidification cracks occasionally FZ. sensitive liquidation occurred HAZ. While PWHT had effect characteristics FZ, notable severity liquation cracking. average numbers per 5 cm weldment 12 14 17 role Zr-inducing solidification HAZ is discussed.