Composition formula of Al-TMs high-entropy alloys derived by cluster-plus-glue-atoms model and its experimental verification

• Published in: China foundry Vol. 19; no. 6; pp. 544 - 550
• Main Authors: Liu, Tian-yu, Shi, Kun, Zhao, Jun, Liu, Shi-bing, Liu, Hong-yu, Liu, Bo-liang, Mei, Xin-min, Ning, Zhao-sheng, Chen, Xiao-ming
• Format: Journal Article
• Language: English
• Published: Singapore Springer Nature Singapore 01.11.2022; State Key Laboratory of Light Alloy Casting Technology for High-end Equipment,Shenyang Research Institute of Foundry Co.,Ltd.,Shenyang 110022,China
• Subjects: Engineering; Machines; Manufacturing; Materials Engineering; Metallic Materials; Processes; Research & Development; Al-TMs high-entropy alloys; A; composition design; short-range order; cluster-plus-glue-atom model; TG146.21
• ISSN: 1672-6421; 2365-9459
• DOI: 10.1007/s41230-022-2140-9

High-entropy alloys (HEAs) are based on solid solutions which characterized by chemical short-range ordering (CSRO), but there is no accurate structural tool to address CSRO characteristic, which obstacles precise composition design for HEAs. In this study, based on the cluster-plus-glue-atoms model, the composition law of Al-TMs (TMs, transition metals) HEAs with BCC and FCC structures was revealed. In BCC structure, with five elements in equi-atomic ratio, the composition formula of Al-TMs HEAs can be expressed by a cluster formula [Al-M 14 ]Al 3 , and in non equi-atomic ratio can be expressed by [Al-M 14 ]Al, where M is the average atom of the TMs. But in FCC structure, both Al-TMs HEAs with five elements in equi-atomic and non equi-atomic ratios can be expressed by a cluster formula [Al-M 12 ]Al. To confirm the effectiveness of cluster formula for Al-TMs, two alloys were designed, [Al-Ti 4 V 3 Nb 4 Mo 3 ]Mo and [Al-Ti 3 V 3 Nb 4 Mo 4 ]Al. Results show that the [Al-Ti 3 V 3 Nb 4 Mo 4 ]Al alloy has both higher strength and higher plastic deformation at room temperature. Besides, [Al-Ti 3 V 3 Nb 4 Mo 4 ]Al alloy shows slower soften effect at 800 °C, contributed to its higher strength. By substituting Ta for some of Mo, the strength of [Al-Ti 3 V 3 Nb 4 Mo 3 Ta]Al at room temperature and high temperature drastically decreases, suggesting that Ta element deteriorates the properties of Al-TMs alloys.