Effect of Al and Ti content on microstructure and properties of laser melting AlxNbTiyV lightweight high entropy alloy

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. AlxNbTiV(x=0.5-7) and AlNbTiyV(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 AlxNbTiV 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 TiAl3 and NbAl3 phases. Ti content in a certain range (y ≤ 7) will not affect the phase structure of the alloy. AlNbTiyV 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 AlxNbTiV 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 AlNbTiyV alloy decreases with the increase of Ti content.