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

Preliminary Exploration on the Preparation of LYSO:Ce Single Crystal Using Verneuil Method

2020 ◽  
Vol 1003 ◽  
pp. 247-253
Author(s):  
Zhi Xin Ma ◽  
Xiao Guo Bi ◽  
Xu Dong Liu ◽  
Xiao Dong Li ◽  
Ji Guang Li ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
High Purity ◽  
Growth Process ◽  
Growth Parameter ◽  
Czochralski Method ◽  
Improved Method ◽  
Crystal Growth Process ◽  
Crystal Fracture

LYSO:Ce single crystal was widely manufactured by Czochralski method. Considering its high cost and the pollution of the crucible, we tried to prepare the crystal by Verneuil method. Unlike Czochralski method, the Verneuil method need the powders with excellent fluidity and high purity. By comparing the powders annealed at 1100°C,1200°C,1300°C,1400°C and 1500°C, we can obtained the needed powders at 1500°C. We also increased the content of silica to satisfy the volatilization in crystal growth process. The single crystal was prepared by changing the growth parameter. We investigated the phase and the microstructure of the powders and observed the microstucture of the crystal fracture. We discussed the improved method of the process of crystal growth.

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 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.

Molecular Dynamics Simulations of the Shear Bands Formation of Single Crystal Bulk Copper during the High Strain Rate Compressive Process

2018 ◽  
Vol 934 ◽  
pp. 30-34
Author(s):  
Yuan Ching Lin ◽  
Chung Jun Shen
Keyword(s):  
Molecular Dynamics ◽  
High Strain Rate ◽  
Strain Rate ◽  
Single Crystal ◽  
High Strain ◽  
Shear Bands ◽  
Md Simulations ◽  
Localized Deformation ◽  
Narrow Region ◽  
Crystal Bulk

In this work, the high strain rate compressive process of single crystal bulk copper was studied by molecular dynamics (MD) simulations. The simulated result indicated that the localized deformation caused the formation of shear bands (SBs). It was found that the formation of shear bands in single crystal was owing to a plenty of the plastic deformations that caused by dislocations slippage or twinning concentrated in a narrow region [1], and the temperature at the shear bands region was rising more quickly than the others.

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