Microstructural Evolution in an Al-Ti-C System Resulting from Laser-Induced Self-propagating High-temperature Synthesis
Y.X. Li and P.K. Bai
A mechanism of self-propagating combustion synthesis of an Al/TiC composite from an Al-Ti-C powder mixture was investigated by observation of the microstructural evolution in a sample. The interaction in the reactant mixtures was studied by differential thermal analysis (DTA). The microstructural evolution in the sample was observed using scanning electron microscopy (SEM) equipped with energy-dispersive spectrometry (EDS), and the phase constituents of the different zones of the sample were inspected by X-ray diffraction (XRD). The results showed that Al3Ti phase formed first and then the Al started to melt. The Ti, especially C particles, dissolved into the Al liquid and formed a Ti–Al–C solution and as a result, TiC grains precipitated out of the saturated liquid solution. With the increasing of temperature the Al3Ti then decomposed and TiC also precipitated from the melt.
Keywords: Al-Ti-C system, Nd:YAG laser, self-propagating high temperature synthesis (SHS), laser induced self-propagating high-temperature synthesis (LISHS), composites, thermodynamic properties, thermochemical properties, laser processing, microstructure evolution