Microstructure and properties of Ni3Al - TiC surface composites formed on Ni3Al using low-energy high-current electron beam

Using scanning and transmission electron microscopy, X-ray diffraction, profilometry, indentation and friction tests we investigated the microstructure and phase composition formation in the near-surface layer, microhardness, surface roughness, resistance to cracking and wear resistance in Ni3Al intermetallic compound and "Ni3Al base - thin powder TiC coating" system processed with low-energy high-current electron beam (LEHCEB). We revealed the crucial role of TiC particles in different behavior of these materials under LEHCEB irradiation with the surface energy density of 8 J/cm(2), accelerating voltage of 30 kV and 10 pulses. The mass fraction of TiC in the near-surface was as much as 22 wt % after three times surfacing. It was found that the presence of TiC thin layer enabled essential microstructure and phase refinement in the near-surface layer of the surface composites and improvement in microhardness and wear resistance. The density of surface cracks in the surface composites is 1.8 lower with respect to TiC-free Ni3Al and the roughness keeps the same. The advantages of LEHCEB processing of intermetallic compounds with thin powder layers are attractive for possible practical application.