Spark Plasma Sintering of Low Alloy Steel Powder

Abstract

Spark Plasma Sintering (SPS) process is a relatively new PM technology used to fabricate metallic parts in shorter time and lower temperature than traditional press-to-sintering technology. In this study, sintering cycles by SPS process were performed in Astaloy CrM steel powder at temperatures between 950 and 1100 °C, with 5 minutes of dwell time and under 60 MPa of uniaxial compaction pressure. The apparent density measured by Archimedes principle, the microstructural investigation by optical microscopy (OM) and scanning electron microscopy (SEM) and the hardness tests by Vicker’s indentation were carried out with the sintered samples. It was observed that at 1050°C more than 98 % of densification was attained. As a low alloy steel powder sintered by SPS an expected high level of densification by the solid state sintering was achieved while hardness is lower than that expected for the Astaloy CrM when sintered mixed with graphite particles.