Development of Ultrafine Grained Austenitic Stainless Steels by High Strain Powder Metallurgy Process

摘要

Chemical compositions and process conditions were examined for improving both strength and toughness in austenitic stainless steels fabricated with high strain powder metallurgy process. Materials with a mean grain size of about 300 nm was able to be fabricated with the addition of Zr and C, and by setting a maximum consolidating temperature at 1123 K. Furthermore, precipitation of M_(23)C_6 and σ phase, which cause brittleness, was able to be suppressed. The materials have tensile strength higher than 1000 MPa and absorbed energy of 150 J comparable to commercial 304 stainless steels.