Tungsten-Based Bcc-Superalloys

Applications from nuclear energy to rockets and jet engines are underpinned by advanced high temperature materials. Whilst state of the art, the performance of current nickel-based superalloys is fundamentally limited to Ni's melting point, T-m = 1455 degrees C. Here, we develop an analogous superalloy concept but with superior high temperature capability by transitioning to a bcc tungsten base, T-m = 3422 degrees C. This strategy involves reinforcing bcc beta-W by beta' TiFe intermetallic compound, which results in impressive high temperature compressive strengths of 500 MPa at 1000 degrees C. This bcc-superalloy design approach has wider applicability to other bcc alloy bases, including Mo, Ta, and Nb, as well as to refractory-metal high entropy alloys (RHEAs). By investigation of the underlying phase equilibria, thermodynamic modelling, characterisation and mechanical properties, we demonstrate the capability of ternary W-Ti-Fe tungsten-based bcc-superalloys as a new class of high temperature materials. (c) 2021 Elsevier Ltd. All rights reserved.