| Abstract Scope |
New materials with improved high temperature performance are sought for nuclear fusion/Generation-IV fission reactors and gas turbines. Refractory metals have exceptionally high melting points >2000°C, far higher than nickel-based fcc-superalloys, <1400°C. However, they do not exploit ordered-intermetallic precipitates, which is a potent strategy in γ-γ’ fcc-superalloys for strength, creep resistance and ductility. There is great scope for the exploitation of this strategy in bcc metals, including within compositionally complex alloys (CCAs, or high entropy alloys, HEAs).
Opportunities for precipitate reinforcement of refractory metal alloys will be discussed. New design strategies exploit the two-phase field bcc β (Ti) to β’ TiFe, whereby precipitates can be produced within a matrix of β (Mo,Ti) and also β (W,Ti). Such precipitation offers superalloy-like β-β’ microstructures where understanding in being developed for (1) Microstructure control, (2) Properties achieved and deformation mechanisms. Such work is critical to realise bcc-superalloys as a new materials class. |