Microstructural evolution during self-propagating high-temperature synthesis of Ni3Al intermetallic

In order to investigate the microstructural evolution of Ni3Al intermetallic from Al and Ni powders during self-propagating high-temperature synthesis (SHS), a combustion front quenching method (CFQM) was used for extinguishing the propagating combustion wave. The microstructures on the quenched sample were observed with scanning electron microscope (SEM) and analyzed with energy dispersive spectrometry (EDS), the temperature of the combustion reaction was tested, and the phase constituent of the synthesized product was inspected by X-ray diffraction (XRD). The results show that the combustion reaction started with melting of the Al particles, and the melting results in partial dissolution of the Ni particles. With interdiffusing between Ni and Al atoms, reaction-diffusing layer of Ni3Al forms on the surface of the undissolving Ni particles and become thicker and thicker continually. Also, the reaction is incomplete, and this is because the coarser Ni and Al powders are used in the present work.