Forming of Ti-Al intermetallic compound by pulsed current sintering

Ti-10mass%Al and Ti-30mass%Al alloys were synthesized by mechanical alloying of elementary Ti powder and Al powder using a planetary ball milling for 360 ks. The obtained Ti-10mass%Al powder milled for 360 ks was identified as α-Ti phase including Al. Ti-30mass% Al powder milled for 360 ks was identified as amorphous state with fine crystals. The mixtures with the composition of Ti-34mass% Al, which were prepared by mixing of MA powders and Al powder, were shown endothermic reaction of Al melt at 930 K in DTA curves. Ti-34mass% Al sample, which was prepared by mixing of mechanically alloyed Ti-30mass% Al powder and Al powder, was consolidated to a complicated shape by pulsed current sintering. After a large amount of shrinkage induced by Al melting was observed in sintering. Ti-Al intermetallic compounds were synthesized by the reaction between mechanically alloyed powder and Al. The sintered compact with a complicated shape cracked during cooling because of the difference of thermal expansion between graphite die and Ti-Al intermetallic compound. The existence of molten Al during the sintering was effective to fabricate a thin sintered compact with a simple shape.