Quartz veins deformed by diffusion creep-accommodated grain boundary sliding during a transient, high strain-rate event in the Southern Alps, New Zealand

2006 ◽  
Vol 28 (5) ◽  
pp. 902-918 ◽  
Author(s):  
Ruth H. Wightman ◽  
David J. Prior ◽  
Timothy A. Little
Keyword(s):  
New Zealand ◽  
Grain Boundary ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Grain Boundary Sliding ◽  
Southern Alps ◽  
Diffusion Creep ◽  
Quartz Veins ◽  
Boundary Sliding

scholarly journals Microstructure Features and Superplasticity of Extruded, Rolled and SPD-Processed Magnesium Alloys: A Short Review

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1766
Author(s):  
Abdul Malik ◽  
Umer Masood Chaudry ◽  
Kotiba Hamad ◽  
Tea-Sung Jun
Keyword(s):  
Grain Boundary ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Rate Sensitivity ◽  
Solute Drag ◽  
Short Review ◽  
Grain Boundary Sliding ◽  
Grain Structure ◽  
Boundary Sliding

In this study, an overview of microstructure features such as grain size, grain structure, texture and its impact on strain rate sensitivity, strain hardening index, activation energy and thermal stability for achieving superplasticity of Mg alloys are presented. The deformation behavior under different strain rates and temperatures was also elaborated. For high elongation to fracture grain boundary sliding, grain boundary diffusion is the dominant deformation mechanism. In contrast, for low-temperature and high strain rate superplasticity, grain boundary sliding and solute drag creep mechanism or viscous glide dislocation followed by GBS are the dominant deformations. In addition, the results of different studies were compared, and optimal strain rate and temperature were diagnosed for achieving excellent high strain rate superplasticity.

Strain-Rate Sensitivity Enhanced by Grain-Boundary Sliding in Creep Condition for AZ31 Magnesium Alloy at Room Temperature

2016 ◽  
Vol 838-839 ◽  
pp. 106-109 ◽  
Author(s):  
Tetsuya Matsunaga ◽  
Hidetoshi Somekawa ◽  
Hiromichi Hongo ◽  
Masaaki Tabuchi
Keyword(s):  
Grain Boundary ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Room Temperature ◽  
High Strain ◽  
Rate Sensitivity ◽  
Grain Boundary Sliding ◽  
Strain Rates ◽  
High Strain Rates ◽  
Boundary Sliding

This study investigated strain-rate sensitivity (SRS) in an as-extruded AZ31 magnesium (Mg) alloy with grain size of about 10 mm. Although the alloy shows negligible SRS at strain rates of >10-5 s-1 at room temperature, the exponent increased by one order from 0.008 to 0.06 with decrease of the strain rate down to 10-8 s-1. The activation volume (V) was evaluated as approximately 100b3 at high strain rates and as about 15b3 at low strain rates (where b is the Burgers vector). In addition, deformation twin was observed only at high strain rates. Because the twin nucleates at the grain boundary, stress concentration is necessary to be accommodated by dislocation absorption into the grain boundary at low strain rates. Extrinsic grain boundary dislocations move and engender grain boundary sliding (GBS) with low thermal assistance. Therefore, GBS enhances and engenders SRS in AZ31 Mg alloy at room temperature.

STUDY ON HIGH STRAIN RATE COMPRESSION SUPERPLASTICITY OF AS-EXTRUDED AZ31 MAGNESIUM ALLOY

2013 ◽  
Vol 27 (19) ◽  
pp. 1341022 ◽  
Author(s):  
FEI LIN ◽  
JIE LI ◽  
HONGWEI ZHAO ◽  
LULU SUN ◽  
ZHITONG CHEN ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
High Strain Rate ◽  
Strain Rate ◽  
Superplastic Deformation ◽  
High Strain ◽  
Orthogonal Experiment ◽  
True Strain ◽  
Grain Boundary Sliding ◽  
Az31 Magnesium Alloy ◽  
Boundary Sliding

The grain size of as-extruded AZ31 magnesium alloy was refined by isothermal annealing pretreatment through orthogonal experiment. By using the Gleeble-3800 thermal simulator, the compression superplasticity of as-extruded AZ31 magnesium alloy was studied. The high strain rate superplastic compression was realized. The process parameters of the superplastic compression were established and the mechanism of the superplastic deformation was analyzed. The effects of deformation temperature and strain rate on the superplastic flow were investigated. The results indicated that at 250°C–300°C and strain rate at 1×10-2 s -1, the true strain values were all more than 2.03. As the temperature was 300°C and the strain rate was 1×10-2 s -1–1×10 s -1, the true strain values were all more than 2.18. The results showed that the as-extruded AZ31 magnesium alloy being refined presented good compression superplasticity. The main mechanism for the superplastic compressive deformation of the as-extruded AZ31 magnesium alloy was grain-boundary sliding, meanwhile, dynamic recrystallization also played a harmonious role during the superplastic deformation.

The Features of Deformation Behavior of Ultra-Fine Grained Titanium and Aluminum Alloys under Conditions of High Strain Rate Superplasticity

2008 ◽  
Vol 584-586 ◽  
pp. 159-163 ◽  
Author(s):  
Evgeny V. Naydenkin ◽  
Ilya V. Ratochka
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Deformation Behavior ◽  
High Strain ◽  
Grain Boundary Sliding ◽  
Recrystallization Process ◽  
Strengthening Effect ◽  
Fine Grained ◽  
Boundary Sliding ◽  
Sliding Resistance

The stress-strain curves at high strain rate superplasticity were analyzed for Ti-6Al-4V and aluminum 1420 industrial alloys in ultra-fine grained state produced by severe plastic deformation. For both alloys the observed strengthening effect can be caused by grain growth under the above mentioned conditions resulting to increase of grain boundary sliding resistance. In the case of aluminum alloy the grain recovery can be accompanied by significant change in phase composition which is also stimulates the recrystallization process.

scholarly journals Grain boundary sliding associated with low strain rate at 1000 °C in recrystallized ODS ferritic steel

2016 ◽  
Vol 9 ◽  
pp. 338-341 ◽  
Author(s):  
R. Kamikawa ◽  
S. Ukai ◽  
N. Oono ◽  
T. Kaito ◽  
T. Torimaru ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Strain Rate ◽  
Ferritic Steel ◽  
Grain Boundary Sliding ◽  
Boundary Sliding ◽  
Low Strain Rate
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