Powder injection moulding of Ti-47.5Al-2.5V-1.0Cr

The injection molding of Ti-47.5Al-2.5V-1.0Cr gas-atomized pre-alloy powders was carried out. The effects of debinding on the contents of residual carbon and oxygen and the microstructure of brown parts and the influences of sintering temperature on the sintered microstructure, density and compressive property of the alloy were investigated. The results showed that the mass fractions of residual carbon and oxygen were 0. 059% and 0.12% respectively under the condition of the thermal debinding temperature of 60012, the holding time of 1 h and vacuum atmosphere. The microstructure was changed from dentritic to nearamma (NG) microstructure when the sintering temperature increased from 600℃ to 1000℃. The specimens densified rapidly at 1410-1450 12 for 1 h. When the vacuum slntering was employed, a near full density of 95% was obtained at 1450℃ after 30min holding, and the compression strength and compression ratio were 2105 MPa and 30.9% respectively, which are near to those of the cast alloy. With the sintering temperature increasing, the amount of y phase decreases gradually. The microstructure was changed from near a lamelar microstructure to a fully lamellar microstructure when the sintering temperature increased from 1410 IE to 1 450℃.