V-stabilized γ′′ phase: a new pathway to enhanced intermediate-temperature ductility in NiCoCr-based multi-component alloys

This work proposes a new design strategy for overcoming the strength-ductility trade-off of gamma ''-strengthened multi-component alloys at intermediate-temperatures. By increasing the V content, the alloy's ductility is enhanced accordingly (650 degrees C tensile-elongation, 9.85%-> 15.97%) without compromising strength. This enhancement is attributed to the improved stability of gamma '', which results in a suppression of brittle epsilon lamellae forming at grain boundaries after deformation and a reduction in gamma/gamma '' lattice misfit. Concurrently, the increasing V content increases the gamma '' volume fraction, offsetting potential strength loss due to the lattice misfit reduction.