粉末注射成形钛合金的脱脂和烧结性能

应用粉末注射成形技术制备出高精度、高性能的异形钛合金零器件。通过多粒度粉末搭配，采用聚甲醛为主组元的多组元粘结剂，制备出高装载量催化脱脂型钛合金喂料，再经真空烧结获得制品。研究了催化脱脂工艺的影响因素以及喂料配比对烧结性能的影响。结果表明:当大（D₅₀=25.28 μm）、中（D₅₀=16.75 μm）、小（D₅₀=12.66 μm）颗粒按质量比17:6:2搭配时，钛合金混合粉末相对振实密度较大，为55%。喂料较佳的催化脱脂工艺为:脱脂温度120 ℃，N₂通入速率120 cm3·min?1，HNO₃气体通入速率1.5 cm3·min?1，脱脂时间6 h，粘结剂脱除率85%。采用全流程控制杂质含量技术，粉末注射成形钛合金制品的烧结性能可以达到相对密度95.9%，拉伸强度933 MPa，抗弯强度1282 MPa，延伸率7.5%，其中C质量分数为0.10%，O质量分数为0.21%。

Debinding and sintering properties of titanium alloys prepared by powder injection molding

Complex shaped titanium alloy parts with the high-precision and high performance were prepared by powder injection molding (PIM) technology. High powder loading titanium alloy feedstock by catalytic debinding was prepared by the multi-granularity powders and the multi-component binder with polyformaldehyde (POM) as the main component, the titanium alloy parts were obtained by vacuum sintering. The influencing factors of the catalytic debinding process and the influence of feedstocks ratio on the properties of the sintered samples were studied. The results show that, when the mass proportion of the large (D₅₀=25.28 μm), medium (D₅₀=16.75 μm), and small (D₅₀=12.66 μm) particles is 17:6:2, the tap density of the mixed titanium alloy powders is as high as 55%. Moreover, the better catalytic debinding process of the feedstock is as follows: the debinding temperature is 120 ℃, the nitrogen feed rate is 120 cm3·min?1, the feed rate of nitric acid gas is 1.5 cm3·min?1, the debinding time is 6 h, and the binder removal rate is 85%. Furthermore, by using the controlling technology of the impurity content in the whole process, the relative density of the titanium alloy products can reach 95.9%, the tensile strength is 933 MPa, the bending strength is 1282 MPa, the elongation is 7.5%, and the mass fraction of C and O is 0.10% and 0.21%, respectively.