Spark Plasma Sintering of Mechanically Milled Hot Work Tool Steel Powder

摘要

Hot work tool steels (HWTS) are characterized by good toughness and high hot hardness but are less wear resistant than other tooling materials, as high speed steel. The addition of hard ceramic particles to steel matrix, that is the production of Metal Matrix Composites (MMC), has been demonstrated to be a good solution to improve the tribological behaviour, but not much work has been done in the field of HWTS. This paper is aimed at investigating the possibility to produce a TiB2-rienforced AISI H13 grade by Spark Plasma Sintering (SPS). Additionally, Mechanical Alloying (MA) has been proposed as an interesting process to improve the MMC microstructure. Therefore a mixed powder blend and a mechanically alloyed powder were sintered and compared to evaluate the advantages of MA. XRD analysis and equilibrium phase diagrams, calculated using ThermoCalc®, were studied to investigate the formation of parasitic phases.