Effect of La2O3 on the in-situ reaction products in Al–CuO–Ti–C system

Abstract

The Aluminum Matrix Composites were manufactured by in situ reactive near liquidus cast of La2O3 powder, aluminum powder, CuO powder, Ti powder, graphite powder with 6063 aluminum alloy as the matrix using the contact reaction method. The x-ray Diffraction, Differential Scanning Calorimeter, Scanning Electron Microscope and Energy Dispersive Spectroscopy were utilized to study the phase evolution and observe the morphology and distribution of the in situ products. The effect of La2O3 on the in situ reaction products in Al–CuO–Ti–C system was investigated. The results manifest that the microstructure of the in situ reaction products in the Al–CuO–Ti–C system is composed of needle-like and lath-like Al3Ti phase, nearly globular-like Al2O3 and granular-like TiC. The microstructure of the in situ reaction products in the Al–CuO–Ti–C-La2O3 system is composed of blocky-like and short rod-like Ti2Al20La phase, globular-like Al2O3 and granular-like TiC. By comparing the two systems, the addition of La2O3 eliminates the needle-like Al3Ti phase of 120 μm and the agglomerated lath-like Al3Ti phase of 50 μm, forms the blocky-like and short rod-like Ti2Al20La of under 20 μm. At the same time, it improves the agglomeration phenomenon of TiC and Al2O3 particles, making them more diffusely distributed in the matrix. The size of TiC and Al2O3 particles reduces from 1 μm to 0.5 μm and 5 μm to 1 μm, respectively.