Improved the microstructures and properties of W−Mo−V high‐speed steel by laser additive manufacturing and niobium alloying

In engineering applications, improving the properties of high-speed steel (HSS) has long been a focus of research. Niobium (Nb), as a strong carbide forming alloy element, is conventionally added to steels to improve their mechanical properties. In the present work, W−Mo−V high-speed steel were deposited by laser additive manufacturing with the aim of investigating the effects of niobium content on the microstructures and mechanical properties. And the niobium content was varied between 0 wt % and 2 wt %. The results show that the content of niobium has a greater influence on the microstructure and mechanical properties of the samples. In particular, with addition of niobium element, the W−Mo−V high-speed steel samples presented a more refined and uniform microstructure compared to the niobium-free sample. Moreover, the addition of niobium can increased the deposition of niobium-rich MC-type carbides in the microstructure and improving the microhardness of W−Mo−V high-speed steel, and also can increased the wear resistance and ductility. Especially for 2 wt % niobium sample, it has excellent wear resistance and high elongation, which were improved by 43.1 % and 32.6 % respectively compared to the W−Mo−V high-speed steel sample.