Phase Evolution, Microstructure, and Mechanical Behaviors of Fe3cr2conialx Multi-Principal Elements Alloys

The Fe 3 Cr 2 CoNiAl x (x = 0.6, 0.7, 0.8, 1.0, 1.1, 1.2) multi-principal elements alloys were prepared, and the microstructure and mechanical behaviors were investigated. The crystal structure changed from a dual-phase structure of FCC plus body-centered-cubic (BCC) structure to a single body-centered-cubic (BCC) structure with the increasing of Al content. By controlling the addition of Al element, the crystalline structure composed of two ordered BCC phase, (1) the primary B2 (P-B2) precipitates with a mean length of 200-300 nm, (2) the secondary B2 (S-B2) precipitates with a mean diameter of 20-50 nm. The compression tests indicated that the Fe 3 Cr 2 CoNiAl 1.2 alloy demonstrated excellent compression properties, whose yield strength and fracture strain is 1464 MPa and 20%, respectively. Furthermore, the strengthening mechanism has been discussed, and provide a useful guidance for the future development of BCC-based multi-principal elements alloys with excellent properties