Distinctive features of the change in structural state and internal stresses present in shear bands of single-crystal zinc

1999 ◽  
Vol 41 (9) ◽  
pp. 1506-1507
Author(s):  
M. E. Bosin ◽  
F. F. Lavrent’ev ◽  
V. N. Nikiforenko
Keyword(s):  
Single Crystal ◽  
Structural State ◽  
Shear Bands ◽  
Internal Stresses ◽  
Distinctive Features

Observation of kink shear bands in an aluminium single crystal fracture specimen

2009 ◽  
Vol 61 (5) ◽  
pp. 465-468 ◽  
Author(s):  
Swapnil D. Patil ◽  
R. Narasimhan ◽  
Raja K. Mishra
Keyword(s):  
Single Crystal ◽  
Shear Bands ◽  
Fracture Specimen ◽  
Crystal Fracture

Survival of Goss Grains during Cold Rolling of a Silicon Steel Single Crystal

2005 ◽  
Vol 495-497 ◽  
pp. 1061-1066 ◽  
Author(s):  
Dorothée Dorner ◽  
Ludger Lahn ◽  
Stefan Zaefferer
Keyword(s):  
Cold Rolling ◽  
Single Crystal ◽  
High Strain ◽  
Shear Bands ◽  
Rolling Process ◽  
Silicon Steel ◽  
Oriented Crystal ◽  
Cold Rolled ◽  
Goss Orientation ◽  
Crystal Volume

A silicon steel single crystal with initial Goss orientation, i.e. the {110}<001> orientation, was cold rolled up to 89 % thickness reduction. Most of the crystal volume rotates into the two symmetrical equivalent {111}<112> orientations. However, a weak Goss component is still present after high strain, although the Goss orientation is mechanically instable under plane strain loading. Two types of Goss-oriented crystal volumes are found in the highly deformed material. We suggest that their origin is different. The Goss-oriented regions that are observed within shear bands form during the cold rolling process. In contrast, those Goss-oriented crystal volumes that are found inside of microbands survive the cold rolling.

scholarly journals Microstructure and microtexture evolution of shear bands in Al–Cu single crystal during asymmetric rolling

2017 ◽  
Vol 128 ◽  
pp. 37-42 ◽  
Author(s):  
Xiaobin Guo ◽  
Yunlai Deng ◽  
Yong Zhang ◽  
Jin Zhang ◽  
Xinming Zhang
Keyword(s):  
Single Crystal ◽  
Shear Bands ◽  
Asymmetric Rolling ◽  
Microstructure And Microtexture

scholarly journals Free-volume dependent pressure sensitivity of Zr-based bulk metallic glass

2009 ◽  
Vol 24 (8) ◽  
pp. 2697-2704 ◽  
Author(s):  
Alban Dubach ◽  
K. Eswar Prasad ◽  
Rejin Raghavan ◽  
Jorg F. Löffler ◽  
Johann Michler ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Free Volume ◽  
Structural State ◽  
Shear Bands ◽  
Compressive Yield Strength ◽  
Pressure Sensitivity ◽  
Constraint Factor ◽  
Shear Transformation Zones

Instrumented indentation experiments on a Zr-based bulk metallic glass (BMG) in as-cast, shot-peened and structurally relaxed conditions were conducted to examine the dependence of plastic deformation on its structural state. Results show significant differences in hardness, H, with structural relaxation increasing it and shot peening markedly reducing it, and slightly changed morphology of shear bands around the indents. This effect is in contrast to uniaxial compressive yield strength, σy, which remains invariant with the change in the structural state of the alloys investigated. The plastic constraint factor, C = H/σy, of the relaxed BMG increases compared with that of the as-cast glass, indicating enhanced pressure sensitivity upon annealing. In contrast, C of the shot-peened layer was found to be similar to that observed in crystalline metals, indicating that severe plastic deformation could eliminate pressure sensitivity. Microscopic origins for this result, in terms of shear transformation zones and free volume, are discussed.

scholarly journals On Localized Deformation and Recrystallization as Damage Mechanisms during Thermomechanical Fatigue of Single Crystal Nickel-Based Superalloys

2011 ◽  
Vol 278 ◽  
pp. 357-362 ◽  
Author(s):  
Johan J. Moverare ◽  
Atsushi Sato ◽  
Sten Johansson ◽  
Magnus Hasselqvist ◽  
Roger C. Reed ◽  
...  
Keyword(s):  
Single Crystal ◽  
Power Plants ◽  
Deformation Behaviour ◽  
Shear Bands ◽  
Thermomechanical Fatigue ◽  
Deformation Bands ◽  
Localized Deformation ◽  
Damage Mechanisms ◽  
Tcp Phases

Thermomechanical fatigue (TMF) in superalloys is growing in importance due to the introduction of advanced cooling systems but also due to the changes in demand and competition within the power generation market; this is requiring many power plants to operate under cyclic conditions. In this paper the TMF behaviour of three different single crystal nickel-based superalloys are compared. It is demonstrated that the deformation and damage mechanisms occurring during TMF are rather different from those traditionally reported for creep or isothermal fatigue. In all cases examined, the deformation is localized within a rather small number of deformation bands. While these bands were found to consist mainly of micro-twins in some alloys, in others they might be better described as slip or shear bands. Furthermore, in some circumstances these bands are prone to recrystallization. In CMSX-4, the intersection points of twins of different orientation act as initiation sites for this process. In the SCA425 alloy – of smaller gamma’ content, lower creep resistance and less great oxidation resistance – twinning is observed infrequently; however the deformation is still very localized and in the distorted gamma-gamma’ microstructure, along the shear bands, recrystallization is observed. Furthermore the recrystallization is enhanced by oxidation due to the development of a gamma’-depleted zone. In CMSX-4, TCP phases precipitated during long term ageing cause a more dispersed deformation behaviour which prevents recrystallization. Our findings confirm the importance of an inhomogeneous microstructure for good TMF resistance.

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