Effect of High Pressure Heat Treatment on Microstructure and Thermal Expansion Coefficients of Cu-Al Alloy

With different high pressure heat treatments on Cu-Al alloy, the effects on microstructure and thermal expansion coefficients of Cu-Al alloy are studied in the paper by optical microscopy, scanning electron microscopy, transmission electron microscopy and expansion instrument etc. The experimental results show that after heat treatment, the structure of Cu-Al alloy was refined obviously and the compactness increased. The grain refinement effect increases at first and then decreases when pressure is increased. When the pressure is 3 GPa, the most obvious is the thinning grain effect. In addition, the high pressure heat treatment can increase Cu-Al alloy thermal coefficient of expansion, when the Cu-Al alloy is treated by 3 GPa pressure and is at 596.37 degrees C. Thermal expansion coefficient is the biggest, 3.1187 x 10(-5)degrees C-1, than that of the same temperature cast state samples increase 99.34%.