Direct synthesis of TiAl alloys through magnesiothermic reduction of an intermediate TiAl2O5 phase was demonstrated at various temperatures and Mg/TiAl2O5 molar ratios. X-ray diffraction (XRD) results verified TiAl alloys could be directly synthesized at a Mg/TiAl2O5 molar ratio of 25 at 900 °C. At lower Mg/TiAl2O5 molar ratios of 12.5 and 5, the desired TiAl alloys underwent a transition from the TiAl alloy to the TiAl2 alloy. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) analysis indicated that a dense Al2O3 film could be easily generated on the surface of the TiAl alloy preventing further oxidation of TiAl alloys. The by-products from the magnesiothermic reduction mainly consisted of MgAl2O4 spinel, which could not be separated from the metallic alloys with a solution of diluted HCl and HNO3 but could be partially separated by particle size. Particle size screening suggested that particles larger than 45 μm mainly contained MgAl2O4 spinel-based by-products and particle size below 45 μm consisted of a mixture of TiAl2 alloys and MgAl2O4 spinel-based by-products.
|Journal||Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science|
|Publication status||Accepted/In press - 2021|
Bibliographical noteFunding Information:
This work was supported by the third stage of the Brain Korea 21 Plus Project of the Division of Creative Materials in 2018 and the National Research Foundation of Korea (NRF) Grant funded by the Korean government (MSIT) (No. 2018R1A2B2006609).
© 2021, The Minerals, Metals & Materials Society and ASM International.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanics of Materials
- Metals and Alloys
- Materials Chemistry