scholarly journals Mechanism of Anomalous Temperature Dependence of Yield Stress by {11\bar22}⟨\bar1\bar123⟩ Secondary Pyramidal Slip in Cadmium Single Crystals

1990 ◽  
Vol 54 (4) ◽  
pp. 427-434 ◽  
Author(s):  
Shinji Ando ◽  
Kazuki Takashima ◽  
Hideki Tonda
Keyword(s):  
Temperature Dependence ◽  
Single Crystals ◽  
Yield Stress ◽  
Anomalous Temperature Dependence ◽  
Anomalous Temperature ◽  
Pyramidal Slip

Deformation Behavior of Magnesium Single Crystals in C-Axis Compression

2007 ◽  
Vol 345-346 ◽  
pp. 129-132 ◽  
Author(s):  
Takaaki Kitahara ◽  
Shinji Ando ◽  
Masayuki Tsushida ◽  
Hiromoto Kitahara ◽  
Hideki Tonda
Keyword(s):  
Fracture Surface ◽  
Single Crystals ◽  
Yield Stress ◽  
Deformation Behavior ◽  
Anomalous Temperature Dependence ◽  
Anomalous Temperature ◽  
Pyramidal Slip ◽  
Axis Compression ◽  
General Deformation ◽  
Increasing Temperature

In general, deformation behavior of magnesium in compression is different from tensile. To investigate deformation behavior of magnesium single crystals, c-axis compression was performed. The crystals were yielded by second order pyramidal slip, and the yield stress shows anomalous temperature dependence (increased with increasing temperature) between 203K and 293K. Yield stress of c-axis compression is bigger than that of a-axis tensile. {10-13} twin and {11-24} twin occurred at 77293K and 77473K respectively. Fracture surface at 77293K was {11-24} and at 473K was {11-22}.

Yield Stress Reversibility and the Operation of Frank-Read Sources in Li2 Alloys in the Anomalous Regime For (111) Slip

1994 ◽  
Vol 364 ◽  
Author(s):  
S. S. Ezz ◽  
P. B. Hirsch
Keyword(s):  
Strain Rate ◽  
Temperature Dependence ◽  
Yield Stress ◽  
Edge Dislocation ◽  
Anomalous Temperature Dependence ◽  
Successful Operation ◽  
Anomalous Temperature ◽  
Small Strains ◽  
Edge Dislocations ◽  
Is Strain

AbstractThe yield stress τy at small strains (≈ 0.01%) is strain rate independent, and has the same anomalous temperature dependence as that of the 0.2% strain. τy is considered to be the stress at which Frank-Read sources operate in a virgin crystal. For successful operation, τy must exceed the stress τs at which screws propagate dynamically through the crystal, and the source dislocation must pass rapidly through the unstable Frank - Read configuration. This can be achieved by the bowing edge dislocation overcoming local obstacles before reaching that configuration. Loops elongated along the screw direction are expected to be formed in the microstrain region. Under certain conditions such loops are unstable on unloading, thereby generating long edge dislocations which can operate successfully as sources at low but not at high temperatures, explaining the reversibility phenomenon.

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