scholarly journals A tale of two mechanisms: Strain-softening versus strain-hardening in single crystals under small stressed volumes

2016 ◽  
Vol 110 ◽  
pp. 48-52 ◽  
Author(s):  
H. Bei ◽  
Y.Z. Xia ◽  
R.I. Barabash ◽  
Y.F. Gao
Keyword(s):  
Strain Hardening ◽  
Single Crystals ◽  
Strain Softening ◽  
Versus Strain

Strain Softening of Aluminum in Shear at Elevated Temperature

2018 ◽  
Vol 941 ◽  
pp. 1490-1494
Author(s):  
Michael E. Kassner ◽  
Roya Ermagan
Keyword(s):  
Elevated Temperature ◽  
Flow Stress ◽  
Single Crystals ◽  
Strain Softening ◽  
Large Strain ◽  
Dislocation Climb ◽  
Taylor Factor ◽  
Shear Texture ◽  
Strain Behavior ◽  
Versus Strain

Large-strain deformation of aluminum in shear consistently evinces strain softening of roughly 15-20%. Most researchers have suggested that this flow stress decrease is a consequence of a decrease in the average Taylor factor as a consequence of a shear-texture. The authors also consider, now, the possibility that changes in the dislocation climb stress induced by the texture could rationalize the softening. This work reports on an analysis of large strain deformation of aluminum single crystals in the softest orientation {111} <110>. Here softening is not observed. However, this result and other in earlier publications are consistent with dislocation climb being the rate-controlling process that also explains the observed stress versus strain behavior.

Anomaly of the Work Hardening of Zn-Cu Single Crystals Oriented for Slip in Secondary Systems

2011 ◽  
Vol 56 (4) ◽  
pp. 1021-1027
Author(s):  
K. Pieła
Keyword(s):  
Strain Hardening ◽  
Single Crystals ◽  
Yield Stress ◽  
Work Hardening ◽  
Temperature Anomaly ◽  
Strain Hardening Exponent ◽  
Plastic Behavior ◽  
Thermal Dependence ◽  
Copper Addition ◽  
Secondary Systems

Anomaly of the Work Hardening of Zn-Cu Single Crystals Oriented for Slip in Secondary SystemsThe copper alloyed (up to 1.5%) zinc single crystals oriented for slip in non-basal systems (orientation close to < 1120 >) were subjected to compression test within a range of temperatures of 77-293K. It has been stated, that Zn-Cu crystals exhibit characteristic anomalies of the thermal dependence of yield stress and of the strain hardening exponent. Both of them are related to the change in type and sequence of active non-basal slip systems: pyramidal of the 1storder {1011} < 1123 > (Py-1) and pyramidal of the 2ndorder {1122} < 1123 > (Py-2). The temperature anomaly of the yield stress results from the change of the slip from Py-2 systems to simultaneous slip in the Py-2 and Py-1 (Py-2 + Py-1) systems, occurring in the preyielding stage. On the other hand, sequential activation of pyramidal systems taking place in advanced plastic stage (i.e. the first Py-2 and next Py-2 + Py-1 systems) is responsible for temperature anomaly of strain hardening exponent. Increase in copper addition favors the activity of Py-2 systems at the expense of Py-1 slip, what leads to a drastic differences in plastic behavior of zinc single crystals.

THE EFFECT OF EXTRANEOUS DEFORMATION ON STRAIN HARDENING IN Cu SINGLE CRYSTALS

1965 ◽  
Vol 6 (8) ◽  
pp. 148-150 ◽  
Author(s):  
Z. S. Basinski ◽  
P. J. Jackson
Keyword(s):  
Strain Hardening ◽  
Single Crystals
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