Superplasticity-Like Behavior, Microstructures and Deformation Mechanism Map in Superlight Mg-6Li-3Zn Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 2504-2510
Author(s):  
Fu Rong Cao ◽  
Ren Guo Guan ◽  
Hua Ding ◽  
Ying Long Li ◽  
Ge Zhou ◽  
...  
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
Strain Rate ◽  
Deformation Mechanism ◽  
Initial Strain Rate ◽  
Lattice Diffusion ◽  
Initial Strain ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Diffusion Activation Energy

Mg-6Li-3Zn alloy sheets were prepared by melting and casting, and heavy rolling with a total reduction of 94%. The high-temperature mechanical behavior, microstructures and deformation mechanisms were investigated. The maximum elongation to failure of 300% was demonstrated at 623K and an initial strain rate of 1.67×10-3s-1. Observations by optical microscope, transmission electron microscope reveal that significant dynamic recrystallization and grain refinement occurred in banded grains at 573K and an initial strain rate of 1.67×10-3s-1, under which the subgrain contour was ambiguous and dislocation distribution was relatively uniform. It is shown by newly constructed deformation mechanism map that the high-temperature deformation mechanism in Mg-6Li-3Zn alloy sheet with banded grains at 573K and an initial strain rate of 1.67×10-3 s-1 is dislocation viscous glide controlled by lattice diffusion, the stress exponent is 3 (strain rate sensitivity exponent 0.33) and deformation activation energy is 134.8 kJ mol-1, which is the same as the lattice diffusion activation energy of magnesium.

High Temperature Deformation Mechanism Maps of NiAl

2004 ◽  
Vol 449-452 ◽  
pp. 57-60
Author(s):  
I.G. Lee ◽  
A.K. Ghosh
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Deformation Mechanism ◽  
Calculation Method ◽  
Deformation Behavior ◽  
Tensile Tests ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Grain Sizes ◽  
Temperature Strain

In order to analyze high temperature deformation behavior of NiAl alloys, deformation maps were constructed for stoichiometric NiAl materials with grain sizes of 4 and 200 µm. Relevant constitute equations and calculation method will be described in this paper. These maps are particularly useful in identifying the location of testing domains, such as creep and tensile tests, in relation to the stress-temperature-strain rate domains experienced by NiAl.

High Temperature Tensile Properties of Mg-5Li-3Al-1.5Zn-2RE Alloys

2012 ◽  
Vol 182-183 ◽  
pp. 189-193
Author(s):  
Ting Qu Li ◽  
M. Gao ◽  
S.H. Wang ◽  
Zhan Yi Cao
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Tensile Properties ◽  
Deformation Mechanism ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Fracture Elongation ◽  
Dominant Deformation Mechanism ◽  
High Temperature Tensile ◽  
High Temperature Tensile Properties

In this paper, the high temperature tensile properties of the LAZ532-2RE alloy prepared by hot extruded processing after vacuum casting was investaged. The tensile properties of the extruded LAZ532-2RE alloy specimens were tested at different temperature with different strain rate. The microstructures near the fractured surfaces were observed using microscope in order to investigate the dominant deformation mechanism. The activation energy was calculated to explain the high temperature deformation mechanism. The result indicated that the strength of LAZ532-2RE alloy was high at the temperature range from 398K to 423K. Meanwhile, the fracture elongation of the alloy reaches 121% at 523K under strain rate 1×10-3s-1.

Comparison of the High-Temperature Deformation of Alumina-Zirconia and Alumina-Zirconia-Mullite Composites

2005 ◽  
Vol 20 (1) ◽  
pp. 13-17 ◽  
Author(s):  
Tiandan Chen ◽  
Martha L. Mecartney
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
Strain Rate ◽  
Stress Exponent ◽  
Creep Behavior ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Reactive Processing ◽  
Lower Activation ◽  
Lower Activation Energy

An alumina-based ceramic codispersed with 15 vol% zirconia and 15 vol% mullite (AZM) was synthesized by reactive processing, and the creep behavior was compared to alumina with 30 vol% zirconia (AZ). Constant stress compressive creep behavior for AZM exhibited a stress exponent of 2 and an activation energy of 770 KJ/mol, while a similar stress exponent but lower activation energy of 660 KJ/mol was found for AZ. The strain rate of AZM, however, was more than twice that of the AZ under the same deformation conditions, indicating a better potential for superplastic shape forming.

Deformation Mechanism Maps for Al-Cu-Mg Alloys Micro-Alloyed with Tin

2011 ◽  
Vol 410 ◽  
pp. 283-286
Author(s):  
P.S. Robi ◽  
Sanjib Banerjee ◽  
A. Srinivasan
Keyword(s):  
High Temperature ◽  
Flow Stress ◽  
Strain Rate ◽  
Deformation Mechanism ◽  
Base Alloy ◽  
Mg Alloy ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Microstructural Investigation

High temperature deformation behavior of Al–5.9%Cu–0.5%Mg alloy and Al–5.9%Cu–0.5%Mg alloy containing 0.06 wt.% of Sn was studied by hot compression tests at various temperatures and strain rates. Addition of trace amounts of Sn into the Al–Cu–Mg alloy system resulted in a significant increase of flow stress for all conditions of temperature and strain rate. 100% and 89% of the flow stress values during hot deformation could be predicted within ± 10% deviation values for the aluminum alloys with and without Sn content, respectively, by artificial neural network (ANN) modeling. From the deformation mechanism maps and microstructural investigation, the safe process regimes for hot working of the base alloy was identified to be at (i) very low strain rate (< 0.003 s−1) at temperature < 450 °C, and (ii) high temperature (> 400 °C) with strain rate > 0.02 s−1. For the micro-alloyed alloy, it was at low strain rates (< 0.01 s-1) for the entire temperature range studied. Flow softening for both alloys was observed to be at low strain rates and was identified to be due to dynamic recrystallization (DRX). The metallurgical instability during deformation was identified due to shear band formation and/or inter-crystalline cracking.

scholarly journals High Temperature Deformation Flow Of A ZK60A Magnesium Alloy After Extrusion

2015 ◽  
Vol 60 (2) ◽  
pp. 1327-1330
Author(s):  
M. Kawasaki ◽  
H.-J. Lee ◽  
M.C. Oh ◽  
B. Ahn
Keyword(s):  
High Temperature ◽  
Magnesium Alloy ◽  
Strain Rate ◽  
Flow Behavior ◽  
Rate Sensitivity ◽  
Initial Strain Rate ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Strain Rates ◽  
Testing Conditions

Abstract Flow behavior of a ZK60A magnesium alloy after continuous casting and subsequent extrusion was examined in tension at a range of strain rates of 3.0×10−6 − 1.0×10−2 s−1 at temperatures of 473-623K. The results demonstrated that the alloy exhibited a maximum elongation of ~250% at 523K when tested at an initial strain rate of 1.0×10−5 s−1 and strain rate sensitivity, m, of ~0.3-0.4 and the activation energy of ~94 kJ/mol were calculated under the testing conditions. The detailed investigation suggested that the high temperature flow of the ZK60A alloy having submicrometer grains demonstrates quasi-superplastic flow behavior controlled by a dislocation viscous glide process.

High temperature deformation of vertical gradient freeze method melt-textured Y1Ba2Cu3O7−x

1999 ◽  
Vol 14 (2) ◽  
pp. 354-358 ◽  
Author(s):  
A. Leenders ◽  
M. Ullrich ◽  
L.-O. Kautschor ◽  
H. C. Freyhardt
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Strain Rate ◽  
Deformation Mechanism ◽  
Vertical Gradient ◽  
Uniaxial Pressure ◽  
Pure Oxygen ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Vertical Gradient Freeze

The deformation behavior of melt-textured Y1Ba2Cu3O7-x (YBCO) prepared by the vertical gradient freeze (VGF) method was investigated by high temperature deformation experiments at temperatures ranging from 850 to 950 °C. The experiments were performed in an atmosphere of pure oxygen under uniaxial pressure with constant strain rates in the range from 1 × 10−5 to 5 − 10−4 s−1. An analysis of the dependence of the steady state flow stress on the strain rate and the deformation temperature reveals that the predominant deformation mechanism is dislocation glide and climb controlled by climb at Y-211 particles and that no significant grain boundary sliding occurs. Furthermore, transmission electron microscopy observations of deformed and undeformed samples support a deformation mechanism based on dislocation movement. The total fracture strain, however, does not depend on the temperature or strain rate. Scanning electron microscopy investigations of the fracture faces of samples deformed until fracture reveal that fracture does not occur within the Y-123 matrix but along platelet boundaries. An improvement of the fracture behavior is expected by introducing large Y-211 particles interconnecting neighboring platelets.

High temperature deformation mechanism of 15CrODS ferritic steels at cold-rolled and recrystallized conditions

2015 ◽  
Vol 466 ◽  
pp. 653-657 ◽  
Author(s):  
Yoshito Sugino ◽  
Shigeharu Ukai ◽  
Naoko Oono ◽  
Shigenari Hayashi ◽  
Takeji Kaito ◽  
...  
Keyword(s):  
High Temperature ◽  
Deformation Mechanism ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Ferritic Steels ◽  
Cold Rolled
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