Lightweight single-phase Al-based complex concentrated alloy with high specific strength
Mingliang Han, Yuan Wu, Xiaobin Zong, Yaozu Shen, Fei Zhang, Hongbo Lou, Xiao Dong, Zhidan Zeng, Xiangyang Peng, Shuo Hou, Guangyao Lu, Lianghua Xiong, Bingmin Yan, Huiyang Gou, Yanping Yang, Xueyan Du, Xiaoyuan Yuan, Yingjie Zhang, Meiyuan Jiao, Xiongjun Liu, Suihe Jiang, Hui Wang, А. А. Rempel, Xiaobin Zhang, Qiaoshi Zeng, Zhaoping Lü
Abstract
Developing light yet strong aluminum (Al)-based alloys has been attracting unremitting efforts due to the soaring demand for energy-efficient structural materials. However, this endeavor is impeded by the limited solubility of other lighter components in Al. Here, we propose to surmount this challenge by converting multiple brittle phases into a ductile solid solution in Al-based complex concentrated alloys (CCA) by applying high pressure and temperature. We successfully develop a face-centered cubic single-phase Al-based CCA, Al55Mg35Li5Zn5, with a low density of 2.40 g/cm3 and a high specific yield strength of 344×103 N·m/kg (typically ~ 200×103 N·m/kg in conventional Al-based alloys). Our analysis reveals that formation of the single-phase CCA can be attributed to the decreased difference in atomic size and electronegativity between the solute elements and Al under high pressure, as well as the synergistic high entropy effect caused by high temperature and high pressure. The increase in strength originates mainly from high solid solution and nanoscale chemical fluctuations. Our findings could offer a viable route to explore lightweight single-phase CCAs in a vast composition-temperature-pressure space with enhanced mechanical properties. By overcoming the limited solubility of other lighter components in aluminum using high pressure and high temperature, a low-density, high specific strength, and single-phase aluminum-based complex concentrated alloy is developed.