Effect of extrusion process parameters on densification and hardness of Al-W alloy

Abstract

The effects of extrusion temperature and extrusion ratio on densification and hardness of Al-W alloy were studied experimentally by means of extrusion deformation of Al-W powder alloy pressed billets. The results show that both the increase of extrusion temperature and extrusion ratio have a positive effect on the densification of Al-W alloy. The relative density increases from 0.943 before hot extrusion to 0.9975, reaching a nearly dense state. The influence of extrusion temperature and extrusion ratio on the hardness of Al-W alloy is more complicate. When the extrusion temperature is constant, the hardness increases with the increase of extrusion ratio. When the extrusion ratio is constant, at the lower extrusion ratio, the hardness first increases and then decreases with the increase of extrusion temperature, and at the higher extrusion ratio, the hardness first decreases and then increases with the increase of extrusion temperature. Microstructure analysis further shows that hot extrusion plastic deformation significantly increases the density of Al-W alloy. As-extruded Al-W alloy with small average grain size is obtained when the extrusion temperature is 540 ℃ and extrusion ratio is 35, and the awerage grain size is about 5 μm.