Thermal expansion behavior of MgO/Cu composite with lower MgO volume fraction

MgO/Cu composites reinforced with 1.0 vol.%, 1.5 vol.%, 2.0 vol.%, 2.5 vol.% and 3.0 vol.% MgO particles were fabricated by powder metallurgy. The effect of MgO particles on the thermal expansion behavior of MgO/Cu composites was studied, and the thermal expansion properties of MgO/Cu composites prepared were evaluated by the coefficient of thermal expansion at the temperatures range from 50 °C to 500 °C. The results show that the introduction of MgO particles significantly reduces the coefficient of thermal expansion of copper matrix. The increased temperature enhances the coefficient of thermal expansion of MgO/Cu composite, whereas more MgO content decreases the coefficient of thermal expansion of MgO/Cu composite. The thermal expansion properties of MgO/Cu composites were calculated by theoretical models. The calculated pressure values at the interface between MgO particles and copper matrix suggest that plastic deformation can occur at 350 °C, which is consistent with the variations of the measured coefficient of thermal expansion.