Microstructural evolution during the combustion synthesis of TiC–Al cermet with larger metallic particles

Abstract

Carbon black powders were incorporated into coarse aluminum and titanium powders, and the mixture was used for a combustion front quenching test. The microstructural evolution in the quenched sample was analyzed with scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). In addition, the combustion temperature and rate were measure, and the phase constituent of the final product was inspected by X-ray diffraction (XRD). The results showed that the combustion reaction started with the melting of the Al particles and formation of Al 3Ti around the Ti particles, and it proceeded in a reaction–dissolution–precipitation mechanism. After melting of the Al and formation of Al 3Ti, the Ti, especially C particles dissolved into the Al liquid and forming Ti–Al–C solution, as a result, TiC grains precipitated out of the saturated liquid solution. With an increase in temperature, Al 3Ti then decomposed and TiC also precipitated from the melt. In the final products, besides TiC particles and Al matrix, a small amount of Al 3Ti was also founded. Also, previous results were explained, and a model corresponding to this mechanism was drawn.