| Ti-45at%Al-1.6at%Mn intermetallic compounds were fabricated from elemental powder mixtures by the reactive sintering method using an Electro-Pressure Sintering(EPS) equipment. Effects of heating rate, holding temperature/time and cooling rate on microstructure and densification were studied. When EPS process was carried out by a high heating rate of 100℃/min, exudation of molten Al from an elemental powder mixture was observed. Such an exudation was found to be preventable by the pre-diffusion treatment below Al melting temperature or EPS process with a low heating rate of 5℃/min. When mold temperature twas held to 1100℃, porosity decreased with increasing in holding time, and a dense titanium aluminide having the porosity below 1% could be obtained at and above the holding time of 30min. Cooling rate during EPS process affected microstructure of sintered material, and a fully homogenized titanium aluminide having a fine lamellar structure was achieved when the cooling rate was lower than 50℃/min after holding at 1250℃ for 120min. |
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