|Budget Amount *help
¥3,200,000 (Direct Cost : ¥3,200,000)
Fiscal Year 2000 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1999 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1998 : ¥1,900,000 (Direct Cost : ¥1,900,000)
The combustion synthesis of dense TiAl intermetallic compound with Ni/Al and Co/Al sintering additive was investigated. The raw Ti/Al(Ti : Al=1 : 1) powder mixed with Ni/Al (Ni : Al= 1 : 1) or Co/Al (Co : Al=1 : 1) was prepared form elemental Ti, Al, Ni, and Co powders. The compacts made from the powders were reacted by the thermal explosion combustion synthesis. After this, density, phases, microstructure, and mechanical properties were measured.
The products by combustion synthesis tend to be porous, HP and HIP treatment were required to obtained dense material. However, the nearly full dense product could be obtained by moderate addition of the sintering additive. In the TiAl combustion synthesis, the liquid quantity was insufficient to promote the densification and too small heat of formation would result in the poor densification. Therefore, the Ni/Al or Co/Al powders were mixed into the Ti/Al powder as the sintering additive.
When the synthesizing additive was added to Ti/Al powder, the product density reached more than 97%. The products consisted of TiAl, Ti_3Al and solidified liquid phase with the grain size of about 25μm. Vickers hardness and compressive strength of the products were compared to those of the TiAl produced by the fusion process. The synthesis condition for the dense TiAl intermetallic compound by the combustion synthesis route could be determined in this study.