Study of the microstructure modulation and phase formation of Ti-Al3Ti laminated composites

It is extremely difficult to eliminate the voids and prepare densely Ti-Al3Ti laminated composites by using existing techniques. In this work, the endothermic semi-solid reaction and the self-propagating synthesis are employed to fabricate Ti-Al3Ti laminated composites. The SEM, EDS and XRD techniques are used to investigate the microstructure and phase formation process of Ti-Al3Ti laminated composites in detail. Results show that the endothermic semi-solid reaction technique can well eliminate the Kirkendall voids, while numerous voids are distributed in composites obtained by the self-propagating synthesis. It demonstrates that the interface phase evolution is Al3Ti, AlTi, AlTi3 and Al2Ti in sequence. The microhardness of both Ti and Al3Ti layers in the composite is tested and presents distinct behaviors with respect to sintering time. This work would suggest an effective way to fabricate densely Ti-Al3Ti laminated composites.