Quantitative study of the mechanical properties of micro-nanostructured 304 stainless steel

Abstract

The austenitic stainless steel specimens with a micro-crystalline/nanocrystalline bimodal structure (micro-nanostructure) were produced by aluminothermic reaction casting method, and the tensile tests and in situ tensile tests were performed. It is found that the stress–strain curve displays the secondary yielding. The uniformly distributed mixed-grain microstructure of the micro-nanostructure is responsible for its strength and toughness. Based on the Hall–Petch relationship of a single-scale and considering the volume fraction of the micro-nanostructure, a mathematical model between the grain sizes and the yield strength is established. The model has a good accuracy when compared with the actual results.