关键词: Ti-Al-V中熵合金, 时效, 密度, 组织, 硬度

Abstract: A new type of Ti-Al-V medium-entropy alloy was prepared by vacuum suspension smelting, and aged at 500 ℃ and 700 ℃ respectively for 2 h. The density of the alloy was determined by using a fully automatic density balance. The effect of aging temperature on microstructure, phase composition and mechanical properties of the alloy was investigated by metallographic microscope, scanning electron microscope, X-ray diffractometer, and Vickers microhardness tester. The results show that the Ti-Al-V medium-entropy alloy is a new type of alloy with light weight (density of 4.18 g/cm³) and high hardness (as-cast of 505 HV), in which BCC matrix and HCP Ti-rich lamellar/granular/acicular precipitates are found in both as-cast and aged states. The amount of precipitated phases in the aged alloy is significantly increased compared with that in as-cast state, and with the increase of aging temperature, the amount of precipitated phases with granular/needle morphologies further increases. The hardness of the alloy is higher in the as-cast state, but the uniformity of the mechanical properties is poor. As the aging temperature increases, the hardness of the alloy gradually decreases, but the mechanical properties are relatively more uniform.

Key words: Ti-Al-V medium-entropy alloy, aging, density, microstructure, hardness