Crack-stimulated generation of deformation twins in nanocrystalline metals and ceramics

2008 ◽  
Vol 88 (8) ◽  
pp. 1137-1151 ◽  
Author(s):  
M.Yu. Gutkin ◽  
I.A. Ovid’ko ◽  
N.V. Skiba
Keyword(s):  
Nanocrystalline Metals ◽  
Deformation Twins

Investigation of the Deformation Twins on the Bending Cross Section of TA2 Titanium Sheet

2020 ◽  
Vol 837 ◽  
pp. 41-45
Author(s):  
Shuai Sun ◽  
Kai Hua Liu
Keyword(s):  
Electron Backscatter Diffraction ◽  
Testing Machine ◽  
Pure Titanium ◽  
Titanium Sheet ◽  
Bending Tests ◽  
Three Point Bending ◽  
Deformation Twins ◽  
Ebsd Technique ◽  
Backscatter Diffraction ◽  
Deformation Area

In order to determine the evolution features of deformation twins for TA2 commercial pure titanium (cp-TA2), the TA2 samples were bent under different bending angles in three-point bending tests via a universal testing machine. The electron backscatter diffraction (EBSD) technique was applied to identify the grain boundaries (GBs) and twin boundaries (TBs) in the bending areas. The results reveal that the type of deformation area would effect the evolution of different deformation twins. It is inferred that the state of stress would promote the multiplication of the same type of deformation twins.

scholarly journals Effect of triple junctions on deformation twinning in a nanostructured Cu–Zn alloy: A statistical study using transmission Kikuchi diffraction

2016 ◽  
Vol 7 ◽  
pp. 1501-1506
Author(s):  
Silu Liu ◽  
Xiaolong Ma ◽  
Lingzhen Li ◽  
Liwen Zhang ◽  
Patrick W Trimby ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Statistical Study ◽  
Nanocrystalline Material ◽  
High Pressure Torsion ◽  
Triple Junctions ◽  
Step Size ◽  
Deformation Twins ◽  
Zn Alloy ◽  
Scanning Electron

Scanning electron microscopy transmission Kikuchi diffraction is able to identify twins in nanocrystalline material, regardless of their crystallographic orientation. In this study, it was employed to characterize deformation twins in Cu/10 wt % Zn processed by high-pressure torsion. It was found that in 83% of grains containing twins, at least one twin intersects with a triple junction. This suggests that triple junctions could have promoted the nucleation of deformation twins. It should be cautioned that this technique might be unable to detect extremely small nanoscale twins thinner than its step size.

Deformation Twins Formed in Nanocrystalline Materials

2006 ◽  
Vol 503-504 ◽  
pp. 125-132 ◽  
Author(s):  
Yuntian T. Zhu
Keyword(s):  
Grain Boundaries ◽  
Nanocrystalline Materials ◽  
Partial Dislocation ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Nucleation And Growth ◽  
Analytical Models ◽  
Partial Dislocations ◽  
Deformation Twins ◽  
Low Strain Rate

Deformation twins have been oberved in nanocrystalline (NC) Al synthsized by cryogenic ball-milling and in NC Cu processed by high-pressure torsion under room temperature and at a very low strain rate. They were found formed by partial dislocations emitted from grain boundaries. This paper first reviews experimental evidences on deformation twinning and partial dislocation emissions from grain boundaries, and then discusses recent analytical models on the nucleation and growth of deformation twins. These models are compared with experimental results to establish their validity and limitations.

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