Modification of the Structure, Phase Composition, and Properties of an Intermetallic-Matrix Composite by Low-Energy High-Current Electron Beam Irradiation

The evolution of the microstructure, phase composition, microhardness, and surface roughness of a Ni3Al–30 vol % TiC composite has been studied using scanning electron microscopy, X-ray diffraction, indentation, and profilometry. The composite was prepared by self-propagating high-temperature synthesis under pressure with the use of a nickel + aluminum + titanium carbide powder mixture and was then irradiated with low-energy high-current electron beam pulses to an energy density of 8 J/cm2. The number of pulses was 10 or 30. The irradiation has been shown to raise the Ni3Al product yield and the volume fraction of the carbide phase in the surface layer of the composite, reduce the particle size of the titanium carbide to a few tens of nanometers, increase the lattice strain in the matrix, reduce its lattice parameter, and increase the surface roughness of the material. As a result, the microhardness of the composite increased by 13%. The physical factors responsible for these changes in structure and properties are discussed.