Detwinning/twin growth-induced phase transformation in a metastable compositionally complex alloy

Extensive experiments have shown that the transformation from face-centered cubic to hexagonal close-packed ε phase usually occurs around coherent Σ3 boundaries. However, in this letter, we reveal a different mechanism metastable dual-phase compositionally complex alloy via systematic high-resolution scanning transmission electron microscopy analysis. The γ matrix can be transformed ɛ (as small as one unit) an incoherent boundary (~30 nm), i.e., facet of boundary. This is assisted by detwinning/twin growth during annealing treatment (900 °C for 60 min).