Structure and Properties of the Surface Layer Obtained by Plasma Surfacing from High-Entropy Molybdenum High-Speed Steel after Complex Processing

A combined treatment was performed on the surface layer formed on 30KhGSA steel by plasma cladding in a nitrogen atmosphere with an M10‑based high‑entropy high‑speed steel. The combined treatment consisted of two cycles of high‑temperature tempering of the cladded layer followed by irradiation with a pulsed electron beam of submillisecond duration (30 J/cm2, 50 μs, 0.3 s–1, 10 pulses). It was found that the combined treatment of the cladding–substrate system is accompanied by an increase in the microhardness of the cladded metal to 8.4 GPa, which is 2.8 times higher than the microhardness of the substrate (30KhGSA steel). It was shown that the microhardness of the surface layer obtained by plasma cladding and subjected to the combined treatment is practically independent of the distance from the substrate. Irradiation of the cladded metal with a pulsed electron beam resulted in formation of a hardened surface layer approximately 100 μm thick. It is suggested that the creation of the hardened surface layer is due to the development of a polycrystalline structure with grain sizes of 4–6 μm, within which a martensitic substructure is observed.