2008 年 72 巻 1 号 p. 21-26
A nanocrystalline Ti50Al50-20 vol%(PSZ-45 mol%Al2O3) composite is fabricated by pulse current pressure sintering of the mixed powder of mechanically milled Ti-50 mol%Al powder and amorphous PSZ-45 mol%Al2O3 powder. The mechanically milled Ti-50 mol%Al powder and amorphous PSZ-45 mol%Al2O3 powder were prepared by the rotating-arm reaction ball milling system. For the powder of the Ti50Al50 -20 vol%(PSZ-45 mol%Al2O3), we have controlled the process variables of pulse current pressure sintering system such as stress, temperature and current. Then, the lowest consolidation temperature necessary to obtain a full densification of compact under the applied stress of 150 MPa is 1405 K at the surface temperature of compact. The X-ray diffraction method confirmed that the nanocrystallization occurs in an overall cross-section of Ti50Al50-20 vol%(PSZ-45 mol%Al2O3) composite with the crystalline size of 28 nm, 16 nm and 16 nm for γ-TiAl, α-Ti and cubic zirconia solid solution respectively. The composite material shows a high 0.2% proof stress value of 2.5 GPa obtained by compression test at room temperature.