Dimensional stability of a metastable FCC high entropy alloy

In this work, a metastable face-centered cubic High Entropy Alloy (HEA) Fe35.0Co28.7Ni24.8Cr1.1Al1.3V4.5Ti1.2Nb2.8Si0.6 was found to exhibit significantly suppressed thermal expansion coefficient (6.0 ppm/K) and stable Young's modulus over a wide temperature range. Experimental and theoretical analyses suggest that both Invar and Elinvar effects were present; in addition, the metastability of this alloy with respect to the first-order phase transition and the magnetic second-order phase transition led to abrupt changes in thermal expansion behavior. The first-order phase transition was associated with the formation of a plate-like D0(19) phase. The magnetic second-order phase transition decreased the Invar effect and the Elinvar effect and resulted in a significant magnetic entropy difference (-3.12 J kg(-1) K-1) in this HEA of interest.

Automated summary

A metastable face-centered cubic High Entropy Alloy exhibited significantly suppressed thermal expansion coefficient and stable Young's modulus over a wide temperature range. Both Invar and Elinvar effects were present in the alloy, and its metastability led to abrupt changes in thermal expansion behavior associated with phase transitions. Additionally, a magnetic second-order phase transition resulted in a significant magnetic entropy difference in the alloy.