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.