The creep behavior of a fully lamellar γ-TiAl based alloy

2019 ◽  
Vol 114 ◽  
pp. 106611 ◽  
Author(s):  
Michael Burtscher ◽  
Thomas Klein ◽  
Svea Mayer ◽  
Helmut Clemens ◽  
Franz Dieter Fischer
Keyword(s):  
Creep Behavior ◽  
Fully Lamellar

The effect of lamellar spacing on the creep behavior of a fully lamellar TiAl alloy

2000 ◽  
Vol 8 (5-6) ◽  
pp. 525-529 ◽  
Author(s):  
C.E. Wen ◽  
K. Yasue ◽  
J.G. Lin ◽  
Y.G. Zhang ◽  
C.Q. Chen
Keyword(s):  
Creep Behavior ◽  
Tial Alloy ◽  
Lamellar Spacing ◽  
Fully Lamellar

Creep behavior of γ-TiAl sheet material with differently spaced fully lamellar microstructures

2002 ◽  
Vol 329-331 ◽  
pp. 840-846 ◽  
Author(s):  
A. Chatterjee ◽  
H. Mecking ◽  
E. Arzt ◽  
H. Clemens
Keyword(s):  
Creep Behavior ◽  
Sheet Material ◽  
Fully Lamellar

Influence of Step Aging on Creep Behavior and Microstructural Evolution of Fine-Grained Fully Lamellar XD TiAl Alloys

2007 ◽  
Vol 539-543 ◽  
pp. 1525-1530
Author(s):  
Han Liang Zhu ◽  
Dong Yi Seo ◽  
Kouichi Maruyama ◽  
Peter Au
Keyword(s):  
Creep Rate ◽  
Microstructural Evolution ◽  
Creep Behavior ◽  
Creep Deformation ◽  
Lamellar Structure ◽  
Aging Condition ◽  
Tial Alloys ◽  
Fine Grained ◽  
Fully Lamellar ◽  
Multiple Step

Fine-grained fully lamellar (FGFL) structures of XD TiAl alloys (Ti-45 and 47Al-2Nb-2Mn+0.8vol.%TiB2) (at.%) were stabilized to varying degrees by different aging treatments. Specimens with and without aging were creep tested at 760°C and 207 MPa. It was found that during creep deformation, degradation of the lamellar structure involving coarsening within the colonies and spheroidization at colony boundaries occurred, forming fine globular structures at the colony boundaries and increasing the creep rate. Aging treatments stabilized the lamellar structure and retarded the coarsening and spheroidization processes during creep deformation. As a result, the aged specimens exhibited lower minimum creep rates and longer creep lives than the unaged specimens. A multiple step aging stabilized the lamellar structure to the greatest extent and suppressed other degradation processes during aging, resulting in the best creep resistance. These results demonstrate that the multiple step aging is the optimal aging condition for stabilizing FGFL XD TiAl alloys.

Observations on the creep behavior of fully-lamellar polycrystalline TiAl: Identification of critical effects

1997 ◽  
Vol 37 (3) ◽  
pp. 315-321 ◽  
Author(s):  
T.A. Parthasarathy ◽  
M.G. Mendiratta ◽  
D.M. Dimiduk
Keyword(s):  
Creep Behavior ◽  
Fully Lamellar

scholarly journals Crystal Plasticity Modeling of Creep in Alloys with Lamellar Microstructures at the Example of Fully Lamellar TiAl

2021 ◽  
Vol 7 ◽  
Author(s):  
Jan E. Schnabel ◽  
Ingo Scheider
Keyword(s):  
Dislocation Density ◽  
Crystal Plasticity ◽  
Creep Behavior ◽  
Elevated Temperatures ◽  
Secondary Creep ◽  
Plasticity Model ◽  
Crystal Plasticity Model ◽  
Path Lengths ◽  
Experimental Findings ◽  
Fully Lamellar

A crystal plasticity model of the creep behavior of alloys with lamellar microstructures is presented. The model is based on the additive decomposition of the plastic strain into a part that describes the instantaneous (i.e., high strain rate) plastic response due to loading above the yield point, and a part that captures the viscoplastic deformation at elevated temperatures. In order to reproduce the transition from the primary to the secondary creep stage in a physically meaningful way, the competition between work hardening and recovery is modeled in terms of the evolving dislocation density. The evolution model for the dislocation density is designed to account for the significantly different free path lengths of slip systems in lamellar microstructures depending on their orientation with respect to the lamella interface. The established model is applied to reproduce and critically discuss experimental findings on the creep behavior of polysynthetically twinned TiAl crystals. Although the presented crystal plasticity model is designed with the creep behavior of fully lamellar TiAl in mind, it is by no means limited to these specific alloys. The constitutive model and many of the discussed assumptions also apply to the creep behavior of other crystalline materials with lamellar microstructures.

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