Densification behavior of tungsten alloy powders during hot isostatic pressing

Abstract

To investigate the densification behavior of tungsten alloy powders during hot isostatic pressing (HIP), the Shima yielding criterion of MSC.Marc was applied to simulate the densification behavior of 93 W-Ni-Fe during HIP. The densification process of tungsten alloy powders and the equivalent stress distribution of capsule during HIP were systematically analyzed. The results show that the densification of tungsten alloy powders during HIP can be divided into several main processes: the first step is expansion, then followed by shrinking, and finally densification with uniform distribution. The density of tungsten alloy reached 93.68% after HIP at 1400 ℃, 140 MPa. Meanwhile, in order to evaluate the quality of the simulation, the HIP experiments were conducted. The deformation of the capsule and the density and mechanical property of tungsten alloy were tested and then compared with simulation results. The results indicate that the maximum relative error of simulation was 1.62% in axial direction and 5.6% in radial direction, and the average relative error of density was only 1.4%. Besides that, by comparing two groups of HIP experiments at different temperatures, the results show that the relative density increased by 2.3% with the temperature increased by 100 ℃.