2013 Volume 60 Issue 12 Pages 510-515
The materials selections of MoSi2/Mo/Nb/γ – TiAl FGMs were performed with the analysis of FGMs database. The stable FGMs criterion without interlayer cracking of ∆α∆T less than 4.3 × 10−3 was derived from FGMs database, where ∆T is the differences in the thermal expansion coefficient and temperature ∆T is between processing and room temperatures. The MoSi2/Mo/Nb/γ – TiAl FGMs were prepared using the spark plasma sintering (SPS) method, followed by siliconized in molten salts. Nb foil was firmly joined to the γ – TiAl surface and Mo foil was firmly joined to the Nb foil. The ∆αNb−Mo∆T and ∆αγ−TiAl−Nb∆T values were consistent with the criterion, where ∆αNb−Mo, ∆αγ−TiAl−Nb, and ∆T arethe differences between the coefficients of thermal expansion of Nb and Mo, and of γ – TiAl and Nb, and ∆T is the difference between the SPS temperature and room temperature. The MoSi2/Mo/Nb/γ – TiAl FGMs were dense and had neither cracks nor voids. The thickness loss of the MoSi2/Mo/Nb/γ – TiAl FGMs was 11 µm after 200 h exposure to air at 1323 K.
