Effect of Nb and Nb2O5 additives on mechano-thermal processing of TiAl/Al2O3 nano-composite
- 123 Downloads
In this research, TiAl matrix nano-composite with Al2O3 reinforcement was obtained by mechanical activation of TiO2 and Al powder mixture and its subsequent heat treatment. Effect of Nb and/or Nb2O5 additions on the process was investigated. Structural changes and thermal behavior of the samples were evaluated by X-ray diffraction and differential thermal analysis, respectively. Moreover, the microstructure was characterized by transmission electron microscopy. The results confirmed the partial dissolution of Nb in Al during the milling stage in the Nb-added samples. The reaction mechanism during heat treatment in the sample without any additives was a two-stage process that was quite similar to the sample with Nb addition. However, Nb2O5 addition led to the progress of reaction through a single stage and with a higher rate. Both additives promoted formation of the Ti3Al phase in the final products. The results confirmed the formation of nano-sized Al2O3 particles in a nano-crystalline Ti–Al matrix with a mean crystallite size of 30 nm.
KeywordsCrystallite Size Mechanical Alloy Nb2O5 Al3Ti TiAl Alloy
The financial support of this study by the Iran National Science Foundation and Iran Nanotechnology Initiative Council is gratefully acknowledged.
- 25.Klug HP, Alexander L (1974) X-ray Diffraction Procedures for Poly-Crystalline and Amorphous Materials. JWiley, New YorkGoogle Scholar
- 26.Cullity BD (1978) Elements of X-Ray Diffraction. Addison-Wesely Publishing Co., USAGoogle Scholar
- 30.Okuno K, Yamashita H, Oida K, Nishikawa O (1987) J Phys C6 48:511Google Scholar
- 31.Porter DA, Easterling KE (1995) Phase transformations in metals and alloys. Chapman & Hall, LondonGoogle Scholar