Effects of Sintering and Compress on Porosity, Mechanical Properties and Conductivity of Cu-Al<sub>2</sub>O<sub>3</sub> Composite Materials Fabricated by Mechano-Chemical Method

Abstract

Nano Al2O3 dispersion - strengthened Cu-matrix composite materials were fabricated by mechano-chemical method. The method carries out at room temperature by mechanical milling in the attritor in 16h hours using the mixtures of CuO, Al and Cu powder ingredients, and then the mixtures were cold pressed into cylindrical samples and sintered at various temperatures (from 700°C to 900°C) and time (from 1 to 3 hours) in argon atmosphere. The XRD pattern and EDS results revealed that Al2O3 phases were formed and dispersed into Cu-matrix during mechano-chemical process. The Al peak disapeared at the end of mechano-chemical process and the final obtained products were Cu-Al2O3 composite materials with Al2O3 content of 3-10% volume. The SEM and EDS results also showed that the particle sizes of Al2O3 were in about (50÷100)nm and uniformly dispersed within the C-matrix. The porosity of materials strongly depends on pressure compress, sintering time and temperature. It decreases with increasing of these parameters and reaches about 5%. The porosity and Al2O3 content affected on mechanical properties of materials, such as micro-hardness and compress strength, due to the dispersion of nano-Al2O3 into Cu-matrix. The conductivity of materials decreases with increasing porosity and Al2O3 content.