Preparation of in situ Cr@Graphene/Fe nanocomposite inoculant and its refining effect on microstructure and properties of W18Cr4V high-speed steel

Abstract

This study investigated the design and preparation of a Cr@Graphene/Fe nanocomposite inoculant via in situ synthesis in a vacuum tube furnace and mechanical grinding in a ball grinder, where material thermodynamics were considered to refine W18Cr4V high-speed steel (HSS). The effect of modification on the microstructure of W18Cr4V HSS was evaluated using high-resolution transmission electron microscopy and X-ray diffraction. The planes of the Fe3W3C phase and planes of the Cr7C3 phase had collaborative points in the reciprocal space, indicating a coplanar relationship between the Fe3W3C and Cr7C3 lattices. This contributed to an improved nucleation rate and refined matrix structure. The mechanical properties of the W18Cr4V HSS, namely hardness, wear mass, and impact energy, exhibited an overall improvement after modification. Specifically, the hardness and impact toughness after modification and heat treatment increased to 65.2 HRC and 0.209 MJ m−2, respectively.