Effects of trace alloying elements on the phase transformation behaviors of ordered ω phases in high Nb-TiAl alloys

2017 ◽  
Vol 113 ◽  
pp. 47-53 ◽  
Author(s):  
Lin Song ◽  
Junpin Lin ◽  
Jinshan Li
Keyword(s):  
Phase Transformation ◽  
Alloying Elements ◽  
Tial Alloys

Design Approaches and Achievements of Novel Wrought TiAl Alloys for Jet Engine Applications

MRS Advances ◽  
2019 ◽  
Vol 4 (25-26) ◽  
pp. 1465-1470
Author(s):  
Hideki Wakabayashi ◽  
Loris J. Signori ◽  
Ali Shaaban ◽  
Ryosuke Yamagata ◽  
Hirotoyo Nakashima ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Phase Transformation ◽  
Hot Workability ◽  
Tial Alloys ◽  
Jet Engine ◽  
Crack Propagation Resistance ◽  
Β Phase ◽  
Transformation Pathway ◽  
Component Systems ◽  
Multi Component System

AbstractDesign approaches and achievements for the development of wrought TiAl alloys to be used for LPT and HPC blades are constructed. In case of Ti-Al-M1-M2 quaternary systems, conventional equivalency concept does not work for the alloy design, and a new thermodynamic database for phase diagram calculations in multi-component systems of the alloys is built by introducing the interaction parameters among four phases of β−Ti, α2−Ti3Al, α−Ti and γ−TiAl phases in the systems, in order to reproduce the experimentally determined phase diagrams. Based on the phase diagram calculations, the composition range of a unique phase transformation pathway of β+α→α→β+γ in the multi-component system can be identified, and thus model alloys with excellent hot workability even at higher strain rate and mechanical properties can be successfully proposed. It can be concluded that an introduction of bcc β phase and the morphology control through the phase transformation pathway make it possible to improve the room temperature ductility, creep and fatigue crack propagation resistance.

Influence of oxygen on microstructure and phase transformation in high Nb containing TiAl alloys

2012 ◽  
Vol 83 ◽  
pp. 198-201 ◽  
Author(s):  
Hong Zhong ◽  
Yanlong Yang ◽  
Jinshan Li ◽  
Jun Wang ◽  
Tiebang Zhang ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Tial Alloys

scholarly journals Effects of Chemical Composition and Austenite Deformation on the Onset of Ferrite Formation for Arbitrary Cooling Paths

Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 540 ◽  
Author(s):  
Aarne Pohjonen ◽  
Mahesh Somani ◽  
David Porter
Keyword(s):  
Phase Transformation ◽  
Chemical Composition ◽  
Hardened Steel ◽  
Computational Method ◽  
Alloying Elements ◽  
Continuous Cooling Transformation ◽  
Ferrite Formation ◽  
Continuous Cooling ◽  
Different Temperatures ◽  
Range Of Values

We present a computational method for calculating the phase transformation start for arbitrary cooling paths and for different steel compositions after thermomechanical treatments. We apply the method to quantitatively estimate how much austenite deformation and how many different alloying elements affect the transformation start at different temperatures. The calculations are done for recrystallized steel as well as strain hardened steel, and the results are compared. The method is parameterized using continuous cooling transformation (CCT) data as an input, and it can be easily adapted for different thermomechanical treatments when corresponding CCT data is available. The analysis can also be used to obtain estimates for the range of values for parameters in more detailed microstructure models.

CYCLIC OXIDATION OF Ti-48%Al-2%Cr-2%Nb-(0~1%)W ALLOYS BETWEEN 800 AND 1000°C IN AIR

2010 ◽  
Vol 17 (02) ◽  
pp. 141-146
Author(s):  
SANG-HWAN BAK ◽  
DONG YI SEO ◽  
SEON-JIN KIM ◽  
JAE CHUN LEE ◽  
DONG BOK LEE
Keyword(s):  
Oxidation Resistance ◽  
Cyclic Oxidation ◽  
Alloying Elements ◽  
Tial Alloys ◽  
Oxidation Characteristics

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 .

Understanding the role of carbon atoms on microstructure and phase transformation of high Nb containing TiAl alloys

2017 ◽  
Vol 124 ◽  
pp. 1-7 ◽  
Author(s):  
Zeen Wu ◽  
Rui Hu ◽  
Tiebang Zhang ◽  
Fan Zhang ◽  
Hongchao Kou ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Tial Alloys
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