PROCESSING OF TIAL-TI2ALN COMPOSITES AND THEIR COMPRESSIVE PROPERTIES

Using elemental powders, combustion reaction was carried out to form intermetallic-ceramic composites in the Ti-Al-N system. Ti and Al powders reacted exothermically in gaseous nitrogen and formed a mixture product which had a fine distribution of the Ti2AlN particles in the matrix TiAl with a small amount of Ti3Al. Subsequently, these reacted products were arc-melted to obtain fully dense button ingots. The resulting composites had about 30 vol. % Ti2AlN, and the Ti2AlN particles were ellipsoidal or columnar in shape with sizes of 2-10-mu-m and appeared to be homogeneously distributed and well bonded to the matrix TiAl. It was found that such composite materials have a high strength at both room and elevated temperatures and some intrinsic compressive ductility at room temperature. Therefore, the processing technique in the present investigation is of interest as a new combustion reaction process to make intermetallic-based composite materials.