Extraordinary Mechanical Properties of a Field‐Assisted Sintering Technique/Spark Plasma Sintering Consolidated Stainless Steel with High Copper Content of 9 wt%

The solidification behavior of a novel X1CrCuNiN 18‐9‐6 (concentrations in wt%) stainless steel is studied by thermodynamic calculations and corresponding microstructure investigations. The thermodynamic calculations of the X1CrCuNiN 18‐9‐6 steel predict a metastable austenitic structure, which is verified by microstructural analyses. In the as‐cast state before heat treatment, a few copper precipitates, mostly over 50 μm in size, are visible, which are located exclusively in the interdendritic regions. The electrode inert gas atomization process is applied to produce a steel powder using a pre‐material in as‐cast state with significantly increased Cu content of 9 wt%. After atomization, despite the rapid cooling, micrometer‐sized copper precipitates form again, which are homogeneously distributed in the microstructure, but are mostly less than 10 μm in size and thus much finer than in the initial cast state. The short processing times during field‐assisted sintering technique/spark plasma sintering makes it possible to produce a bulk material with a porosity of less than 1%. Miniature samples produced from the as‐sintered material exhibit uniform elongation values of 30%–40% with a tensile strength of about 640 MPa under tensile loading conditions.