Diamond and Low Carbon Steel Interaction at Melting Temperature of Fe-C Eutectic

Abstract

Abstract The structure, elemental and phase composition of the products formed during the contact interaction of diamond with low-carbon steel in vacuum at the Fe-C eutectic melting temperature were studied. Cylindrical tablets made of low carbon steel (less than 0.1 % wt. C), and pyramid shaped natural diamond crystals were used as a contact pairs. Diamond crystals were mounted by their flat base on the horizontal surface of steel tablet and a load was applied to the diamond crystals top. Contact samples were sintered in a vacuum furnace at a maximum heating temperature of ~1165 °C. Sintered diamond-steel tablet samples were studied by optical and scanning electron microscopy, X-ray diffraction analysis. It was shown that the initial steel tablet with a ferrite-perlite structure passed cementation during sintering in contact with diamond. The most intensive cementation is undergone by the non-melted upper layer of the steel tablet ~110 μm thick, which adjoined the Fe-C eutectic melt during sintering. The microhardness of this layer was ~4945 MPa. As it deepens into steel tablet a gradual transition of structure from perlite-cementite to perlite and further to the initial ferrite-perlite microstructure is observed. Herewith, the microhardness changes from ~ 4945 to 1570 MPa.