Application of metal injection molding process to fabrication of bulk parts of TiAl intermetallics

In the present study, a metal injection molding (MIM) process was applied to the fabrication of bulk parts of TiAl intermetallics, and effects of sintering parameters on densification of fabricated parts were investigated. The specimens sintered at 1350 °C showed about the same densification as the ones sintered at 1400 °C, while grains and pores were finer, and thus 1350 °C was chosen as the sintering temperature. In the sintered specimens after debinded in an H₂ atmosphere, Al₂O₃ precipitates were observed around pores. The densification decreased with increasing heating rate up to the sintering temperature. It was also found that the sintering time increased the densification without grain coarsening. The optimal heating rate was found to be 3 °C/min, and the densification reached a near-full level of 98.8% when sintered at 1350 °C for 30 h. These findings suggested a useful idea to successfully fabricate TiAl intermetallic parts by the MIM process.