Al2O3 particle-reinforced ZL109 composite was prepared by in situ reaction between CuO and Al2O3 . The microstructure was observed by means of OM, SEM and TEM. The Al2O3 particles in sub-micron sizes distribute unifo...Al2O3 particle-reinforced ZL109 composite was prepared by in situ reaction between CuO and Al2O3 . The microstructure was observed by means of OM, SEM and TEM. The Al2O3 particles in sub-micron sizes distribute uniformly in the matrix, and the Cu displaced from the in situ reaction forms net-like alloy phases with other alloy elements. The hardness and the tensile strength of the composites at room temperature have a slight increase as compared to that of the matrix. However, the tensile strength at 350℃ has reached 90.23 MPa, or 16.92 MPa higher than that of the matrix. The mechanism of the reaction in the CuO/AI system was studied by using of differential scanning calorimetry（DSC） and thermodynamic calculation. The reaction between CuO and Al involves two steps. First, CuO reacts with Al to form Cu20 and Al2O3 at the melting temperature of the matrix alloy, and second, Cu20 reacts with Al to form Cu and Al2O3 at a higher temperature. At ZL109 casting temperature of 750- 780 ℃, the second step can also take place because of the effect of exothermic reaction of the first step.展开更多
文摘Al2O3 particle-reinforced ZL109 composite was prepared by in situ reaction between CuO and Al2O3 . The microstructure was observed by means of OM, SEM and TEM. The Al2O3 particles in sub-micron sizes distribute uniformly in the matrix, and the Cu displaced from the in situ reaction forms net-like alloy phases with other alloy elements. The hardness and the tensile strength of the composites at room temperature have a slight increase as compared to that of the matrix. However, the tensile strength at 350℃ has reached 90.23 MPa, or 16.92 MPa higher than that of the matrix. The mechanism of the reaction in the CuO/AI system was studied by using of differential scanning calorimetry（DSC） and thermodynamic calculation. The reaction between CuO and Al involves two steps. First, CuO reacts with Al to form Cu20 and Al2O3 at the melting temperature of the matrix alloy, and second, Cu20 reacts with Al to form Cu and Al2O3 at a higher temperature. At ZL109 casting temperature of 750- 780 ℃, the second step can also take place because of the effect of exothermic reaction of the first step.
