Abstract

The microstructure and mechanical property of hot-pressed Al_2O_3/Cu composites with a different temperature for atmosphere changing from H_2 to Ar have been studied. When atmosphere-changed from H_2 to Ar gas at 1450°C, the hot-pressed composite was characterized by inhomogeneous microstructure and low fracture strength. On the contrary, when atmosphere-changed at low temperature of 1100°C the composite showed more homogeneous microstructure, higher fracture strength and smaller deviation in strength. Based on the thermodynamic consideration and microstructural analysis, it was interpreted that the Cu wetting behavior relating to the formation of CuAlO_2 is probably responsible for strong dependence of microstructure on atmosphere changing temperature. The reason for a strong sensitivity of fracture strength and especially of its deviation to atmosphere changing temperature was explained by the microstructural inhomogeneity and by the role of CuAlO_2 phase on the interfacial bonding strength.

• Keywords: Nanocomposites;Sintering atmosphere;Microstructure;Mechanical properties;