Modification of diffusion boride layers by an electron beam on the surface of 5KhNM steel

The results of surface hardening of 5KhNM alloy steel samples by the method of complex saturation with boron and copper (borocoppering) with subsequent modification by an electron beam were presented. The steel samples' microstructure, microhardness, elemental, and phase compositions were studied after complex borocoppering and subsequent electron beam processing. It has been shown that the effect of an electron beam significantly increases the thickness of the boride layer, leading to a transition from the needle-like structure of the layer to a fine-grained submicron structure, as well as a decrease in microhardness and an increase in the plasticity of the layer. XRD analysis revealed the absence of highly porous phases FeB and Cr$_2$B$_5$ after electron beam processing. X-ray spectral microanalysis revealed that the boron content in the layer decreased from 16 to 6 wt.% after processing, and the copper content, on the contrary, increased from 2.6 to 4 wt.% away from the surface.