scholarly journals Quantitative analysis of microstructures produced by creep of Ti–48Al–2Cr–2Nb–1B: Thermal and athermal mechanisms

1998 ◽  
Vol 13 (3) ◽  
pp. 625-639 ◽  
Author(s):  
M. A. Morris ◽  
M. Leboeuf
Keyword(s):  
Tial Alloy ◽  
Mechanical Twinning ◽  
Deformation Mechanisms ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Pipe Diffusion ◽  
Thermally Activated ◽  
Fine Grain ◽  
Hardening Process ◽  
Secondary Stage

A γ-based TiAl alloy with equiaxed microstructure and fine grain size has been studied to analyze the deformation mechanisms responsible for the creep behavior. The microstructures produced by creep and high temperature deformation have been examined by TEM to obtain information about the different aspects characterizing the primary and secondary stages of creep. Mechanical twinning has been confirmed to occur in a fraction of the grains that never exceeds 50% while 1/2 ‹110› dislocations are active within all the γ grains. The twins are only responsible for a small amount of strain, but they lead to a subdivision of the microstructure and determine (directly or indirectly) the hardening process observed during the primary stage of creep. We have proposed that during the secondary stage the creep rate is determined by the unblocking of pinned dislocations by processes such as a pipe diffusion or cross slip that allow thermally activated glide of 1/2‹110› dislocations on (001) planes.

scholarly journals Microstructural Characterization of Friction-Stir Processed Ti-6Al-4V

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 976 ◽  
Author(s):  
Sergey Mironov ◽  
Yutaka S. Sato ◽  
Hiroyuki Kokawa ◽  
Satoshi Hirano ◽  
Adam L. Pilchak ◽  
...  
Keyword(s):  
Electron Backscatter Diffraction ◽  
Microstructural Characterization ◽  
Mechanical Twinning ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Misorientation Distribution ◽  
Friction Stir ◽  
Α Phase ◽  
Ebsd Technique ◽  
Backscatter Diffraction

The present work was undertaken to shed additional light on the globular-α microstructure produced during FSP of Ti-6Al-4V. To this end, the electron backscatter diffraction (EBSD) technique was employed to characterize the crystallographic aspects of such microstructure. In contrast to the previous reports in the literature, neither the texture nor the misorientation distribution in the α phase were random. Although the texture was weak, it showed a clear prevalence of the P1 and C-fiber simple-shear orientations, thus providing evidence for an increased activity of the prism-<a> and pyramidal <c+a> slip systems. In addition, the misorientation distribution exhibited a crystallographic preference of 60° and 90° boundaries. This observation was attributed to a partial α→β→α phase transformation during/following high-temperature deformation and the possible activation of mechanical twinning.

High Temperature Deformation Behavior of Beta-Gamma TiAl Alloy

2007 ◽  
Vol 539-543 ◽  
pp. 1531-1536 ◽  
Author(s):  
J.S. Kim ◽  
You Hwan Lee ◽  
Young Won Kim ◽  
Chong Soo Lee
Keyword(s):  
High Temperature ◽  
Deformation Behavior ◽  
Tial Alloy ◽  
Microstructural Analysis ◽  
Processing Condition ◽  
Simulation Method ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Β Phase ◽  
Dynamic Materials

In this study, high-temperature deformation behavior of newly developed beta-gamma TiAl alloys was investigated in the context of the dynamic-materials model (DMM). Processing maps representing the efficiency of power consumption for microstructure evolution were constructed utilizing the results of compression test at temperatures ranging from 1000oC to 1200oC and strain rates ranging from 10-4/s to 102/s and Artificial Neural Network simulation method. With the help of processing map and microstructural analysis, the optimum processing condition for the betagamma TiAl alloy was investigated. The role of β phase was also discussed in this study.

Interaction of high-temperature deformation mechanisms

1992 ◽  
Vol 23 (11) ◽  
pp. 3135-3140 ◽  
Author(s):  
M. G. Zelin ◽  
H. S. Yang ◽  
R. Z. Valiev ◽  
A. K. Mukherjee
Keyword(s):  
High Temperature ◽  
Deformation Mechanisms ◽  
High Temperature Deformation ◽  
Temperature Deformation
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