A repetitive thermomechanical process to produce nano-crystalline in a metastable austenitic steel

Nano-crystalline grains of about 100 nm were obtained in a metastable austenitic steel by a repetitive thermomechanical process consisting of conventional cold rolling and annealing. The nano-grained austenite was transformed on annealing from the strain-induced martensite, which had formed during cold rolling. The nano-structured austenitic steel exhibits not only high strength (above 1 GPa) but also good elongation (above 30%).