Publikations Einzelansicht

Titel: Synthesis of the cubic Z-phase in the Ti-Al-O system by a powder metallurgical method
 

Autor(en):
 
V. Shemet, P. Karduck, H. Hoven, B. Grushko, W. Fischer und W.J. Quadakkers
 
Journal: Intermetallics
Jahr: 1997
Band: 5
Seite(n): 271-280


Zusammenfassung:
The formation of protective or non-protective oxide scales on γ-TiAl alloys is closely related to the composition of the subsurface depletion layer. Recently it was shown that in the depletion layer a cubic Z-phase is formed, which was until then not known in the Ti-Al-O phase diagram. In the present study a method was developed to synthesise this cubic phase by a powder metallurgical method.<br> It was found that the Z-phase can be produced by a reaction between the α-TiOx solid solution and aluminium using self-propagating high temperature synthesis (SHS). The phase analysis and microstructural characterisation of the Ti-O-Al sintering products show that at 900-950 °C the Z-phase exists in equilibrium with γ-TiAl(O) and α-Al2O3 as well as with Ti2O and α-Ti3Al(O) ordered solid solutions. According to X-ray and electron diffraction data the Z-phase has a primitive cubic structure of one of the space groups P 213 or P 4132 and has a composition close to Ti5Al2O3. The lattice parameter of the cubic phase was determined to be a = 0.691 ±0.001 nm.

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Publikations Einzelansicht

Titel: Synthesis of the cubic Z-phase in the Ti-Al-O system by a powder metallurgical method
 

Autor(en):
 
V. Shemet, P. Karduck, H. Hoven, B. Grushko, W. Fischer und W.J. Quadakkers
 
Journal: Intermetallics
Jahr: 1997
Band: 5
Seite(n): 271-280


Zusammenfassung:
The formation of protective or non-protective oxide scales on γ-TiAl alloys is closely related to the composition of the subsurface depletion layer. Recently it was shown that in the depletion layer a cubic Z-phase is formed, which was until then not known in the Ti-Al-O phase diagram. In the present study a method was developed to synthesise this cubic phase by a powder metallurgical method.<br> It was found that the Z-phase can be produced by a reaction between the α-TiOx solid solution and aluminium using self-propagating high temperature synthesis (SHS). The phase analysis and microstructural characterisation of the Ti-O-Al sintering products show that at 900-950 °C the Z-phase exists in equilibrium with γ-TiAl(O) and α-Al2O3 as well as with Ti2O and α-Ti3Al(O) ordered solid solutions. According to X-ray and electron diffraction data the Z-phase has a primitive cubic structure of one of the space groups P 213 or P 4132 and has a composition close to Ti5Al2O3. The lattice parameter of the cubic phase was determined to be a = 0.691 ±0.001 nm.

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