The effect of La2O3 addition on intermetallic-free aluminium matrix composites reinforced with TiC and Al2O3 ceramic particles

In this work, intermetallic-free aluminium matrix composites reinforced with TiC and Al2O3 ceramic particles were successfully prepared via an in situ reaction of Al-Ti-C-CuO-La2O3 during self-propagating high-temperature synthesis. The effect of adding the rare earth metal oxide La2O3 was studied by using differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, optical microscopy and Brinell hardness tests. The results showed that La2O3 could promote the wettability of the C and Al melt in the Al-Ti-C-CuO system. The final products of the in situ reaction for the 2.5Al-1Ti-1.2C-0.5CuO-0.005La(2)O(3) system were TiC particles and Al2O3 particles, and the system was free of intermetallic compounds. The prepared aluminium matrix composites were greatly refined with an average grain size of 20.6 mu m. The intermetallic-free aluminium matrix composites reinforced with TiC and Al2O3 particles showed up to two times higher Brinell hardness value than the matrix 6063 aluminium alloy.