Transformation-induced extraordinary ductility in an ultrafine-grained alloy with nanosized precipitates

An ultrafine-grained (UFG) alloy with nanosized precipitates was fabricated by strain-induced martensitic transformation and the reverse transformation through a conventional rolling and annealing process. The UFG alloy possesses a high yield stress (860 MPa), five times higher than that of coarse-grained alloy, very high tensile stress (1140 MPa), and exceptional uniform elongation of above 30% due to both precipitates and strain-induced martensite that form in these alloys during tensile tests.