A low-density high-entropy dual-phase alloy with hierarchical structure and exceptional specific yield strength

A high-entropy dual-phase AlTiVCoNi alloy with a low density of similar to 6.24 g cm(-3) is developed, and it consists of a hierarchical structure, including an ordered L2(1) phase, a disordered body-centered-cubic (BCC) solid-solution phase, and nano-sized L2(1) precipitates embedded in the BCC phase. It is found that this new alloy shows phase stability after the heat treatment at 1200 degrees C for 24 h, and the compressive yield strength of this annealed alloy is approximately equal to that of the as-cast condition, similar to 1.6 GPa. This alloy displays an exceptional compressive strength at room temperature and at 600 degrees C, with the specific yield strengths of similar to 261 and similar to 210 MPa g(-1) cm(3), respectively. The semi-coherent interface of the L2(1) and the BCC phases makes the alloy phase stable and regulates the work-hardening mechanism. Local dynamic-recrystallization behavior and grain evolution are observed in the as-prepared alloy during compression at 800 and 1000 degrees C, which results in the high-temperature softening. This alloy with a muti-phase hierarchical structure would provide a new paradigm for the development of next-generation low-density, high-entropy structural materials for high-temperature applications.

Automated summary

A high-entropy dual-phase AlTiVCoNi alloy with a low density and hierarchical structure has been developed. The alloy exhibits phase stability due to the semi-coherent interface of the L2(1) and BCC phases, and shows exceptional compressive strength at both room and high temperatures.