The microstructures of titanium aluminide based composites have been investigated using optical microscopy, scanning electron microscopy, energy dispersive spectrometry, transmission electron microscopy, and scanning transmission electron microscopy. The composites were in the form of pellets of ~ 3 mm dia. produced by laser melting various mixtures of titanium, aluminium, and silicon carbide using 800 W laser power, 3 mm beam diameter, and 0·5 s pulse time. In all the processed samples, titanium and aluminium were completely melted andformed an alloy, whereas, SiC particles were partially dissolved leading to the enrichment of the alloy matrix with silicon and carbon. The aluminium contents of the matrixes of the composites spanned the rangefrom ~15 to ~ 78 at.-%. In the 15-42 at.-%Al range, the phasesformed during solidification were f3 titanium solid solution, TiC, and Tis(Si,Al)]; f3 and TiASi,Al)] occurred together as a eutectic constituent. During solid state cooling, f3phase transformed to either martensite or an L/.,2 + y mixture, depending on the alu.minium content of the matrix. At 57 at.-%Al the matrix solidified toform y, TiC, and Tis (Si,Al)]. The composite with 78 at.-%Al contained dendrites of Ti(Al,Si)] and
interdendritic aluminium