Numerical Simulation And Experimental Analysis For The Hydrostatic Extrusion Of93W-Ni-Fe Alloys

Due to unique mechanical properties, tungsten based alloys were widely used in national defense and civil field. With increasing the application, higher comprehensive mechanical properties of tungsten based alloys were required. In this work, to obtain the optimized technologic parameter, numerical simulation for the hydrostatic extrusion of93W-Ni-Fe alloy was carried out based on the elasto-plastic finite element method. The simulation results were proved by the hydrostatic extrusion experiment. The effect of vacuum annealing and extrusion ratio on the mechanical properties and microstructure of93W-Ni-Fe alloy were investigated.The stress strain curve of93W-Ni-Fe alloy was measured by the Instron3369mechanical testing machine. The hydrostatic extrusion process of93W-Ni-Fe alloy and the influence of process parameters on the extrusion products were simulated by ANSYS software. The fracture and microstructure of extruded bars was analyzed by Scanning Electricity Microscope (SEM). The results are as follow:(1)The results of simulation of93W-Ni-Fe alloy hydrostatic extrusion indicated that the optimized technologic parameters of friction factor, extrusion ratio and mould angle were0-0.1,1.8and45°, respectively. The surface of extruded bar was smooth without cracks, which was basically in agreement with the results of simulations.(2) When the extrusion ratio of hydrostatic extrusion of93W-Ni-Fe alloy increased from1.6to2.1, the slenderness increased from2.58to2.95, the connectivity decreased from0.50to0.46, the elongation decreased from3.10%to1.00%, meanwhile, the tensile strength of93W-Ni-Fe increased from1323.61MPato1600.00MPa.(3) The93W-Ni-Fe hydrostatic extrusion bars with the extrusion ratio of1.6were vacuum annealed at850℃,950℃,1050℃and1150℃for2h, respectively. As temperature increased, the shape of tungsten grain was transformed from strip to nearly spherical, the tensile strength of93W-Ni-Fe gradually decreased, and the values were1323.61MPa,1220.97MPa,996.10MPa and981.31MPa, respectively. However, the elongations increased obviously, which were3.10%,6.70%,11.14%and24.36%, respectively. According to the mechanical properties, the best annealing temperature ranged from850℃to950℃.This article includes44graphs,3tables and75references.