MICROSTRUCTURE STABILIZATION IN A RAPIDLY SOLIDIFIED TYPE-304 STAINLESS-STEEL - INFLUENCE ON TENSILE PROPERTIES

Tensile properties and their relationship with microstructural features were investigated for a rapid solidification processed (RSP) type 304 stainless steel (SS) extruded powder material and compared with those of a conventionally processed type 304 SS. Significant improvements in tensile strength were observed up to 800-degrees-C (maximum test temperature) for the RSP alloy. Stable and fine microstructural features, including grain size, small matrix precipitates, high residual dislocation density, and a high population of nanosized void/cavities, were observed in the RSP specimens after heat treatments to 0.9T(m). The microstructural features directly responsible for strengthening the RSP alloy were small grain size and the residual dislocation density.