Ti-47．5Al-2．5V-1．0Cr注射成形

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

以Ti-47．5Al—2．5V-1．0Cr（原子分数，％）气雾化预合金粉末为原料，采用粉末注射成形工艺制备了Ti舢合金材料，研究了该TiAl合金脱脂工艺对脱脂坯碳氧残留量和组织的影响规律及烧结工艺对烧结体显微组织、密度和压缩性能的影响规律．结果表明：在脱脂温度600℃、保温时间为1h和真空脱脂气氛条件下脱除坯体中剩余粘结剂，坯体中残余碳氧含量（质量分数）分别为0．059％和0．12％；脱脂温度从600℃升到1000℃，粉末由枝状组织转变为近γ组织；烧结温度在1410～1450℃，保温时间在1h以内，烧结体可以快速致密化；在1450℃保温30min，烧结体相对密度可以达到95％，烧结体的抗压强度为2105MPa，压缩率达到30．9％，接近铸态合金力学性能；随烧结温度升高，烧结体中的γ相逐渐减少，组织由近片层组织逐渐转变为全片层组织．

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 ℃.