Al和Ti含量对激光熔炼Al_(x)NbTi_(y)V轻质高熵合金组织与性能的影响

Effect of Al and Ti content on microstructure and properties of laser melting Al_(x)NbTi_(y)V lightweight high entropy alloy

轻质高熵合金在结构材料轻量化方面显示出巨大的应用价值,激光熔炼和激光增材制造技术因其极端冶金条件,为高熵合金研制提供了新思路。采用激光熔炼技术制备Al_(x)NbTiV(x=0.5~7)和AlNbTi_(y)V(y=1~7)纽扣试样,并对其相结构、显微组织和硬度进行了系统研究。结果表明:Al含量对合金相结构和显微组织有显著影响,Al含量低(x≤2)时,Al_(x)NbTiV合金由BCC单相固溶体组成;Al含量高(2<x≤7)时,合金出现金属间化合物,随着Al含量增加由BCC,TiAl相转变为TiAl_(3),NbAl_(3)相。Ti含量在一定范围(y≤7)不会影响合金相结构,AlNbTi_(y)V合金均由BCC单相固溶体组成。Al,Ti含量对合金硬度均有较大影响,Al_(x)NbTiV合金由BCC单相组成时,合金硬度随着Al含量的增加硬度升高,金属间化合物的出现使合金硬度不再随Al含量的变化而变化;AlNbTi_(y)V合金硬度随Ti含量的增加而降低。

The lightweight high entropy alloys have shown great application value in the lightweight structural materials.Laser melting and laser additive manufacturing technology provide new ideas for the development of high entropy alloys due to their extreme metallurgical conditions.Al_(x)NbTiV(x=0.5-7)and AlNbTi_(y)V(y=1-7)button samples were prepared by laser melting technology,and their phase structure,microstructure and hardness were systematically studied.The results show that the Al content has a significant effect on the phase structure and microstructure of the alloy.When the Al content is low(x≤2),the Al_(x)NbTiV alloy is composed of BCC single-phase solid solution.When the Al content is high(2≤x≤7),intermetallic compounds appear in the alloy.With the increase of Al content,the BCC and TiAl phases change into TiAl_(3) and NbAl_(3) phases.Ti content in a certain range(y≤7)will not affect the phase structure of the alloy.AlNbTi_(y)V alloys are composed of BCC single-phase solid solution.The content of Al and Ti has a great influence on the hardness of the alloy.When the Al_(x)NbTiV alloy is composed of BCC single phase,the hardness of the alloy increases with the increase of Al content,and the appearance of intermetallic compounds makes the hardness of the alloy no longer change with the change of Al content.The hardness of AlNbTi_(y)V alloy decreases with the increase of Ti content.