Preparation and synthesis thermokinetics of novel Al-Ti-C-La composite master alloys

The new type of Al-Ti-C-La master alloy was prepared by commercial pure Al, Ti powder, graphite powder, Al powder and La2O3 powder by aluminum melt in-situ reaction method. The microstructure and the effect on commercial pure aluminum of Al-Ti-C-La master alloy have been studied by means of X-ray diffraction (XDR), scanning electron microscopy (SEM) equipped with energy-dispersive spectrometry (EDS). The synthesis thermodynamics and kinetics of Al-Ti-C-La master alloy were analyzed. The experiment shows that Al-Ti-C-La master alloy is composed of Al, Al3Ti, TiC and Ti2Al20La. The refining performance of the prepared Al Ti C La master alloy is obviously better than that of Al-Ti-C master alloy when the addition of rare earth oxide La2O3 is 10 wt% and the preparation temperature is 930 degrees C. The analysis of thermodynamic calculation and the process of kinetics demonstrate that, in the preparation process of Al-Ti-C-La master alloy, firstly, Al reacts with Ti to produce Al3Ti, C reacts with Ti and Al3Ti to form TiC based on the aluminothermy reaction. Rare earth oxide La(2)O(3 )and C powder react with Ti powder and O(2 )in the air occur to generate CO, TiC, [La] atoms and LaC2. [La] atoms adsorb on the surface of Al3Ti to form the new rare earth compounds Ti2Al20La. (C) 2018 Elsevier B.V. All rights reserved.