Forming of Ti-Al Intermetallic Compound by Pulsed Current Sintering

摘要

Ti-10 mass percent Al and Ti-30 mass percent Al alloys were synthesized by mechanical alloying of elementary Ti powder and Al powder using a planetary ball million for 360 ks. The obtained Ti-10 mass percent Al powder milled for 360 ks was identified as alpha-Ti phase including Al. Ti-30 mass percent Al powder milled for 360 ks was identified as amorphous state with fine crystals. The mixtures with the composition of Ti-34 mass percent 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-34 mass percent Al sample, which was prepared by mixing of mechanically alloyed Ti-30 mass percent 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.