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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 Al合金材料,研究了该Ti Al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1 h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1 000℃,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1 h以内,烧结体可以快速致密化;在1450℃保温30 min,烧结体相对密度可以达到95%,烧结体的抗压强度为2105 MPa,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 TiAl alloy material was prepared by powder injection molding using the gas-atomized pre-alloyed powder of Ti-47.5Al-2.5V-1.0Cr (atomic fraction,%) as raw material. The effect of degreasing on Ti The content of oxygen, the influence of the microstructure and the sintering process on the microstructure, density and compressive properties of the sintered body were studied.The results showed that the green body was degreased under the conditions of degreasing temperature of 600 ℃, holding time of 1 h and vacuum degreasing atmosphere In the remaining binder, the residual carbon content of the body (mass fraction) were 0.059% and 0.12% respectively; degreasing temperature rose from 600 ℃ to 1000 ℃, the powder transformed from dendrite to near-γ organization; sintering temperature at 1410 ~ 1450 ℃, holding time is less than 1 h, the sintered compact can be rapidly densified; the relative density of the sintered compact can reach 95% at 1450 ℃ for 30 min, the compressive strength of the sintered compact is 2105 MPa, the compressibility reaches 30.9% Close to the mechanical properties of as-cast alloy. With the increase of sintering temperature, the γ phase in the sintered body decreases gradually, and the microstructure of the sintered body gradually changes from the near-layer structure to the whole-layer structure.