Improvement of the Oxidation Resistance of TiAl Alloys Using Controlled Gaseous Fluorination

2019 ◽  
Vol 11 (15) ◽  
pp. 37-48 ◽  
Author(s):  
Patrick J. Masset ◽  
Michael Schütze
2020 ◽  
Vol 106 (7-8) ◽  
pp. 3203-3215 ◽  
Author(s):  
Prince Valentine Cobbinah ◽  
Wallace Matizamhuka ◽  
Ronald Machaka ◽  
Mxolisi Bredon Shongwe ◽  
Yoko Yamabe-Mitarai

2010 ◽  
Vol 17 (02) ◽  
pp. 141-146
Author(s):  
SANG-HWAN BAK ◽  
DONG YI SEO ◽  
SEON-JIN KIM ◽  
JAE CHUN LEE ◽  
DONG BOK LEE

Ti-48%Al-2%Cr-2%Nb-(0, 0.5, 1) at.%W alloys were synthesized via the powder metallurgical route, and cyclically oxidized at 800, 900, or 1000°C in air for up to 100 h in order to find the effects of W on their oxidation characteristics. At 800°C, they oxidized relatively slowly, and the scales were thin and adherent. At 900°C, the scales began to spall locally. At 1000°C, they spalled repetitively during oxidation. Cr , Nb , and W improved the cyclic oxidation resistance of TiAl alloys. The oxides formed were TiO2 and Al2O3 , which contained the alloying elements of Cr , Nb , and W . Nitrides formed were TiN and Ti2AlN .


2005 ◽  
Vol 22 (3) ◽  
pp. 309-314 ◽  
Author(s):  
A. Donchev ◽  
H.-E. Zschau ◽  
M. Schütze

2021 ◽  
Vol 8 ◽  
Author(s):  
X. Gong ◽  
R. R. Chen ◽  
Y. Wang ◽  
Y. Q. Su ◽  
J. J. Guo ◽  
...  

In order to improve the oxidation resistance of TiAl alloys, NiCoCrAlY coatings with different amounts of Sm2O3 were prepared by laser cladding on TiAl alloys. The microstructure and oxidation behavior of the coatings were investigated by isothermal oxidation tests at 900°C. The results indicated that the grains of the coatings were refined by Sm2O3. The fine grain reduced the crack sensitivity of the doped coatings and promoted the transformation of θ-Al2O3 to α-Al2O3. Therefore, the internal oxidation of the coatings and the growth rate of the oxide films were reduced. The segregation of Sm at grain boundary inhibited the outward diffusion of Ti, thus reducing the excessive oxidation of Ti. In addition, the oxidation mechanism of the coating was changed from simultaneous diffusion of Al and O to predominant inward diffusion of O. The oxidation resistance of the doped coatings was significantly improved. However, excessive Sm2O3 is detrimental to the improvement of the oxidation resistance. The oxidation resistance of 3 wt% Sm2O3 is the best.


2010 ◽  
Vol 638-642 ◽  
pp. 1374-1378 ◽  
Author(s):  
Patrick J. Masset ◽  
Rossen Yankov ◽  
Andreas Kolitsch ◽  
Michael Schütze

Surfaces of titanium aluminides were treated by fluorine either physically using Plasma Immersion Ion Implantation (PI³) or chemically with a F-based polymer. By controlling the fluorination parameters, both treatments improve the oxidation resistance even in the presence of sulfur dioxide (0.1 vol%). No sulfur was detected in the oxide scale although thermodynamic calculations predict the formation of sulfides. The inward diffusion of oxygen and nitrogen in the alloy was found to be reduced in the presence of SO2.


2014 ◽  
Vol 54 ◽  
pp. 814-819 ◽  
Author(s):  
Seong-Woong Kim ◽  
Jae Keun Hong ◽  
Young-Sang Na ◽  
Jong-Taek Yeom ◽  
Seung Eon Kim

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