Combining multiscale structure and TRIP effect to enhance room temperature tensile properties of 304 stainless steel by cryogenic cyclic plastic strengthening

In this paper, 304 austenitic stainless steel was strengthened by cryogenic cyclic plastic strengthening (CCPS) method to obtain a material that combined multiscale structure and transformation-induced plasticity (TRIP) effect. After strengthening, there were harder small α′-martensite particles limited to the dense slip bands skeleton in the austenite coarse grains, which led to dynamic strain partitioning during uniaxial tension tests at room temperature. In addition, martensitic transformation occurred steadily throughout the strain range of the tensile tests. At room temperature, the characteristics of cryogenic transformation were maintained and the saturation value of the transformation was increased. The strengthened material showed an excellent combination of high strength and ductility at room temperature.