Abstract

Ti-37.5at%Si elemental powder mixtures were mechanically alloyed by a high-energy ball mill, followed by CIP (cold isostatic pressing) and HIP (hot isostatic pressing) for different processing conditions. Only elemental phases (Ti and Si) were observed for the 5 min mechanically alloyed (MA 5 min) powder, but only Ti_5Si_3phase was observed for the 30 min mechanically alloyed (MA 30 min) powder. Ti_5Si_3phase was observed for the HIPed compact of MA 5 min and 30 min powders at 150 and 190 MPa for 3 hr at 1000°C. For the HIPed compacts, the highest sintered density was obtained to be 99.5% of theoretical density by a HIP step at 1350°C at 190MPa for 3hr. The hardness values of the HIPed Ti_5Si_3compacts at 1350°C at 150/190 MPa for 3hr were higher than HRC 76. The densification and mechanical property of HIPed Ti_5Si_3compacts was found to depend on more HIP temperature than HIP pressure.

• Keywords: mechanical alloying;Ti_5Si_3;HIP(hot isostatic pressing);