Yield stress of aged Cu-Fe alloy single crystals at low temperatures

1994 ◽  
Vol 13 (12) ◽  
pp. 922-924
Author(s):  
Y. Watanabe ◽  
H. Miura ◽  
M. Kato ◽  
A. Sato
Keyword(s):  
Single Crystals ◽  
Yield Stress ◽  
Low Temperatures

The mechanical properties of pure iron tested in compression over the temperature range 2 to 293 °K

1967 ◽  
Vol 261 (1121) ◽  
pp. 253-287 ◽  
Keyword(s):  
Mechanical Properties ◽  
Flow Stress ◽  
Strain Rate ◽  
Single Crystals ◽  
Yield Stress ◽  
Low Temperatures ◽  
Pure Iron ◽  
Constant Strain Rate ◽  
Frictional Stress ◽  
Strain And Strain Rate

The mechanical properties of pure iron single crystals and of polycrystalline specimens of a zone-refined iron have been measured in compression over the temperature and strain rate ranges 2.2 to 293 °K and 7 x 10 -7 to 7 x 10 -3 s -1 respectively. Various yield stress parameters were determined as functions of both temperature and strain rate, and the reversible changes in flow stress produced by isothermal changes of strain rate or by changes of temperature at constant strain rate were also measured as functions of temperature, strain and strain rate. Both the temperature variation of the flow stress and the strain rate sensitivity of the flow stress were generally identical for the single crystals ( ca. 0.005/M carbon) and the polycrystalline specimens ( ca. 9/M carbon). At low temperatures, the temperature dependence of the yield stress was smaller than that of the flow stress at high strains, probably because of the effects of mechanical twinning, but once again the behaviour of single and polycrystalline specimens was very similar. Below 10 °K, both the flow stress and the extrapolated yield stress were independent of temperature. The results show that macroscopic yielding and flow at low temperatures are both governed by the same deformation mechanism, which is not very impurity sensitive, even in the very low carbon range covered by the experiments. The flow stress near 0 °K is ca. 5.8 x 10 -3 u where [i is the shear modulus. On the basis of a model for thermally activated flow, the activation volume at low temperatures (high stresses) is found to be ca. 5 b 3 . The exponent in the empirical power law for the dislocation velocity against stress relation is ca. 3 near room temperature, but becomes quite large at low temperatures. The results indicate that macroscopic deformation at low temperatures is governed by some kind of lattice frictional stress (Peierls-Nabarro force) acting on dislocations.

Microstructure and Plastic Deformation Behavior of Ni3V Single Crystals

2007 ◽  
Vol 561-565 ◽  
pp. 407-410 ◽  
Author(s):  
Koji Hagihara ◽  
Mayumi Mori ◽  
Yukichi Umakoshi
Keyword(s):  
Plastic Deformation ◽  
Single Crystals ◽  
Yield Stress ◽  
High Temperatures ◽  
Low Temperatures ◽  
Deformation Behavior ◽  
Plastic Deformation Behavior ◽  
Rapid Drop

Plastic deformation behavior of Ni3V with D022 structure was examined using the single crystals containing two dominant variants of three. At [557] loading orientation, {111}1/6<112] twinning is dominantly operative at low temperatures, but {111}1/2<112] slip is activated at high temperatures accompanied by a rapid drop of yield stress.

PLASTIC ANISOTROPY OF TANTALUM, NIOBIUM, AND MOLYBDENUM

1967 ◽  
Vol 45 (2) ◽  
pp. 1075-1089 ◽  
Author(s):  
P. J. Sherwood ◽  
F. Guiu ◽  
H. C. Kim ◽  
P. L. Pratt
Keyword(s):  
Single Crystals ◽  
Yield Stress ◽  
Applied Stress ◽  
High Temperatures ◽  
Low Temperatures ◽  
Plastic Anisotropy ◽  
Anisotropic Behavior ◽  
Screw Dislocations ◽  
Strain Behavior ◽  
Tension And Compression

The stress–strain behavior of single crystals of tantalum, niobium, and molybdenum has been studied in both tension and compression in the temperature range 4.2–400 °K. The crystals were stressed in both the [Formula: see text] and the [Formula: see text] directions.At high temperatures, the yield stress of all three metals is independent of the direction and sense of the applied stress. At low temperatures, the yield stress depends markedly on the orientation of the crystals and the sense of the applied stress. This anisotropic behavior cannot be satisfactorily explained in terms of any of the mechanisms proposed so far, such as the mobility of jogs in screw dislocations, or the dissociation of a/2 [Formula: see text] screw dislocations on {112} planes.

Plastic Deformation Behavior of Oriented Ni3V Crystals with D022 Structure

2006 ◽  
Vol 980 ◽  
Author(s):  
Koji Hagihara ◽  
Mayumi Mori ◽  
Yukichi Umakoshi
Keyword(s):  
Plastic Deformation ◽  
Single Crystals ◽  
Yield Stress ◽  
High Temperatures ◽  
Low Temperatures ◽  
Deformation Behavior ◽  
Plastic Deformation Behavior ◽  
Deformation Modes ◽  
Rapid Drop

AbstractPlastic deformation behavior of Ni3V with D022 structure was examined using the single crystals containing two dominant variants of three. Three deformation modes were confirmed to be operative depending on temperature and loading orientation. {111}1/6<112] twinning and/or {111}<110] slip is dominantly operative at low temperatures, but {111}1/2<112] slip is activated at high temperatures accompanied by a rapid drop of yield stress.

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