Abstract:
Based on the previous preparation of refractory high entropy alloy wire, NbMoTaNiCr refractory high entropy alloy wire was designed and developed, and the forming experiment of NbMoTaNiCr refractory high entropy alloy was carried out by using the tungsten inert gas welding (TIG) rotating arc additive manufacturing technology. The effects of current, electrode spacing, wire feed speed and accumulation speed on the forming quality of NbMoTaNiCr high entropy alloy were studied by orthogonal forming experiments with five factors and five levels. The results show that the forming quality of NbMoTaNiCr refractory high entropy alloy is most affected by current and wire feed speed. The forming characteristic parameters of weld bead increase first and then decrease with the increase of current, wire feed speed and accumulation speed. According to the orthogonal experiment results, the optimal process parameters are current 120 A, wire feed speed 8 mm·s
−1, accumulation speed 120 mm·min
−1, gas flow rate 18 L·min
−1, electrode spacing 1 mm. The NbMoTaNiCr refractory high entropy alloy is mainly composed of FCC phase and a small amount of μ phase. The average hardness of the forming layer surface of NbMoTaNiCr refractory high entropy alloy prepared in this experiment reaches HV 911, which exceeds that of other high temperature resistant high entropy alloys reported in all literatures and reaches the level of amorphous hardness. The yield strength of the forming layer is 545.5 MPa, the fracture strain is 5.5%, and the fracture mechanism is cleavage fracture.