Effect of the B4C content on the structure and thermal expansion coefficient of the Al–5% Cu alloy-based metal-matrix composite material

Abstract

The Al–5% Cu alloy-based metal-matrix composite materials reinforced with 5-μm B₄C particles have been produced using mechanical mixing-in method. A process of addition of the B₄C particles into the melt has been developed. A homogeneous distribution of the B₄C reinforcing particles in the metal-matrix composite matrix was obtained. Using X-ray diffraction analysis, the formation of Al₃BC and AlB₂ phases has been revealed at the interphase matrix/particle boundary, which indicates a good interaction in the phases. With increasing B₄C content in the matrix alloy, an insignificant increase in the porosity (from 1 to 3.1%) occurs. The average linear thermal-expansion coefficient is reduced from 24.5 to 22.6 × 10^–6 K^–1 in the temperature range of 20–100°C.