【摘要】 以Nb、Mo、Ta、W、V、Cr等金属粉末为原料,采用机械合金化与放电等离子烧结相结合的方法制备难熔Nb Mo TaWVCr高熵合金,研究球磨时间对合金的物相组成、显微组织与压缩性能的影响。结果表明,经过40 h球磨即可实现机械合金化,得到单相体心立方(BCC)结构的NbMoTaWVCr高熵合金粉末。随球磨时间延长,粉末的晶粒细化,微观应变增大。经1 500℃放电等离子烧结后的块体合金由BCC基体和Laves相以及氧化物相组成,析出相含量随球磨时间延长而增加。随球磨时间延长,NbMoTaWVCr难熔高熵合金的压缩屈服强度先增加后减小,塑性逐渐减小,在球磨40 h下的NbMoTaWVCr高熵合金块体材料具有最佳力学性能,压缩屈服强度和塑性应变分别为3 416 MPa和5.3%。更多还原

【Abstract】 Refractory NbMoTaWVCr high entropy alloy(HEA) was fabricated by combination of mechanically alloying(MA) and spark plasma sintering(SPS) using powders of Nb, Mo, Ta, W and V as raw materials. The effects of milling time on phase composition, microstructure evolution and mechanical properties were investigated. The results show that mechanical alloying can be achieved after 40 h ball milling, and the single-phase BCC NbMoTaWVCr high entropy alloy powder is obtained. With the increase of milling time, the grain size is refined and the micro strain increases.The bulk alloy sintered by SPS at 1 500 ℃ consists of BCC matrix, Laves phase and oxide phase. The content of precipitated phase increases with the increase of milling time. With the increase of milling time, the compressive yield strength increases first and then decreases and the plasticity decreases gradually. The NbMoTaWVCr refractory high entropy alloy sintered from powders milled for 40 h exhibits an excellent yield strength of 3416 MPa and plastic strain of 5.3%.更多还原