Interface structures in Al-Nb2O5 nanocomposites processed by high-pressure torsion at room temperature

This work presents a study related to the grain refinement of an aluminum A2618 alloy achieved by High-Pressure Torsion (HPT) known as a process of Severe Plastic Deformation (SPD). The HPT is conducted on disks of the alloy under an applied pressure of 6 GPa for 1 and 5 turns with a rotation speed of 1 rpm at room temperature. The HPT processing leads to microstructural refinement with an average grain size of ~250 nm at a saturation level after 5 turns. Gradual increases in hardness are observed from the beginning of straining up to a saturation level. This study thus suggests that hardening due to grain refinement is attained by the HPT processing of the A2618 alloy at room temperature.

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Hardening mechanism of commercially pure Mg processed by high pressure torsion at room temperature

Materials Science and Engineering A ◽

10.1016/j.msea.2014.09.068 ◽

2014 ◽

Vol 619 ◽

pp. 95-106 ◽

Cited By ~ 43

Author(s):

Xiao Guang Qiao ◽

Ya Wei Zhao ◽

Wei Min Gan ◽

Ying Chen ◽

Ming Yi Zheng ◽

...

Keyword(s):

High Pressure ◽

Room Temperature ◽

High Pressure Torsion ◽

Hardening Mechanism ◽

Commercially Pure

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The significance of self-annealing at room temperature in high purity copper processed by high-pressure torsion

Materials Science and Engineering A ◽

10.1016/j.msea.2016.01.027 ◽

2016 ◽

Vol 656 ◽

pp. 55-66 ◽

Cited By ~ 38

Author(s):

Yi Huang ◽

Shima Sabbaghianrad ◽

Abdulla I. Almazrouee ◽

Khaled J. Al-Fadhalah ◽

Saleh N. Alhajeri ◽

...

Keyword(s):

High Pressure ◽

High Purity ◽

Room Temperature ◽

High Pressure Torsion ◽

Purity Copper

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Intragranular deformation mechanisms in calcite deformed by high-pressure torsion at room temperature

Mineralogy and Petrology ◽

10.1007/s00710-019-00690-y ◽

2020 ◽

Vol 114 (2) ◽

pp. 105-118

Author(s):

Roman Schuster ◽

Gerlinde Habler ◽

Erhard Schafler ◽

Rainer Abart

Keyword(s):

High Pressure ◽

Twin Boundary ◽

Brittle Failure ◽

Room Temperature ◽

High Pressure Torsion ◽

Confining Pressure ◽

Temperature Deformation ◽

Orientation Relationships ◽

High Confining Pressure ◽

Confining Pressures

AbstractPolycrystalline calcite was deformed to high strain at room-temperature and confining pressures of 1–4 GPa using high-pressure torsion. The high confining pressure suppresses brittle failure and allows for shear strains >100. The post-deformation microstructures show inter- and intragranular cataclastic deformation and a high density of mechanical e$$ \left\{01\overline{1}8\right\} $$011¯8 twins and deformation lamellae in highly strained porphyroclasts. The morphologies of the twins resemble twin morphologies that are typically associated with substantially higher deformation temperatures. Porphyroclasts oriented unfavorably for twinning frequently exhibit two types of deformation lamellae with characteristic crystallographic orientation relationships associated with calcite twins. The misorientation of the first deformation lamella type with respect to the host corresponds to the combination of one r$$ \left\{10\overline{1}4\right\} $$101¯4 twin operation and one specific f$$ \left\{01\overline{1}2\right\} $$011¯2 or e$$ \left\{01\overline{1}8\right\} $$011¯8 twin operation. Boundary sections of this lamella type often split into two separated segments, where one segment corresponds to an incoherent r$$ \left\{10\overline{1}4\right\} $$101¯4 twin boundary and the other to an f$$ \left\{01\overline{1}2\right\} $$011¯2 or e$$ \left\{01\overline{1}8\right\} $$011¯8 twin boundary. The misorientation of the second type of deformation lamellae corresponds to the combination of specific r$$ \left\{10\overline{1}4\right\} $$101¯4 and f$$ \left\{01\overline{1}2\right\} $$011¯2 twin operations. The boundary segments of this lamella type may also split into the constituent twin boundaries. Our results show that brittle failure can effectively be suppressed during room-temperature deformation of calcite to high strains if confining pressures in the GPa range are applied. At these conditions, the combination of successive twin operations produces hitherto unknown deformation lamellae.

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Microstructures and Mechanical Property of Ni Processed by High-Pressure Torsion and Their Evolution upon Annealing

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.114.45 ◽

2006 ◽

Vol 114 ◽

pp. 45-50 ◽

Cited By ~ 1

Author(s):

Zhi Qing Yang

Keyword(s):

High Pressure ◽

Grain Boundaries ◽

Room Temperature ◽

High Pressure Torsion ◽

Small Difference ◽

Dynamical Evolution ◽

Peripheral Region ◽

Lattice Defects ◽

Grain Sizes ◽

Xrd And Tem

XRD, TEM, microhardness and thermal analysis were carried out on a series of Ni samples produced by high-pressure torsion (HPT). The evolution of microstructures and their inhomogeneity were investigated. The local microstrain showed dynamical oscillations as a function of the HPT rotations, demonstrating dynamical evolution of lattice defects during the procedure. Both XRD and TEM showed that a small difference in grain sizes remains even after 5 revolutions of HPT with smaller grain sizes at the peripheral region of the sample. The higher microhardness at the peripheral region is the result of the smaller grain sizes and the higher density of lattice defects, compared with the central region. Thermal treatment at a heating rate of 20K/min from room temperature to 473K did not result in decreased microhardness, but increased by about 10% for samples treated with not more than 3 rotations of HPT. The increase in microhardness was attributed to further grain refinement, the formation of a larger fraction of high-angle grain boundaries and grain boundaries being closer to equilibrium after recovery.

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Processing Different Magnesium Alloys through HPT

Materials Science Forum ◽

10.4028/www.scientific.net/msf.783-786.2617 ◽

2014 ◽

Vol 783-786 ◽

pp. 2617-2622 ◽

Cited By ~ 2

Author(s):

Livia Raquel C. Malheiros ◽

Roberto B. Figueiredo ◽

Terence G. Langdon

Keyword(s):

Plastic Deformation ◽

High Pressure ◽

Magnesium Alloys ◽

Room Temperature ◽

High Pressure Torsion ◽

Structure Refinement ◽

Hardness Distribution ◽

Metallic Materials ◽

Processing Conditions ◽

Significant Structure

High-Pressure Torsion (HPT) is widely used to refine the structure of metallic materials through the use of severe plastic deformation. This technique is used in this report to process different magnesium alloys using various processing conditions. The high hydrostatic pressure allows processing of these materials at room temperature without cracking. The structure was characterized and hardness distribution was determined at different areas of the processed samples. The results show significant structure refinement and increased hardness. The evolution of the structure and hardness depends on the alloying and HPT processing conditions.

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Superplasticity of Ultra-Fine Grained 7075 Alloy Processed by High-Pressure Torsion

Materials Science Forum ◽

10.4028/www.scientific.net/msf.794-796.807 ◽

2014 ◽

Vol 794-796 ◽

pp. 807-810 ◽

Cited By ~ 2

Author(s):

Seungwon Lee ◽

Zen Ji Horita

Keyword(s):

High Pressure ◽

Room Temperature ◽

High Pressure Torsion ◽

Applied Pressure ◽

Tensile Tests ◽

Initial Strain ◽

Strain Rates ◽

Fine Grained ◽

Al 7075 ◽

7075 Alloy

An Al 7075 alloy (5.63mass%Zn-2.56mass%Mg-1.68mass%Cu-0.21mass%Fe-0.19mass%Cr-0.14mass%Si-0.02mass%Ti with balance of Al) was processed by high-pressure torsion (HPT) under an applied pressure of 6 GPa for 1, 3 and 5 revolutions with a rotation speed of 1 rpm at room temperature. Vickers microhardness saturated to a level of 220 Hv after the HPT processing and the grain size was refined to 120 nm at the state of the hardness saturation. Tensile tests were conducted with initial strain rates from 2.0 × 10-4 to 2.0 × 10-2 s-1 at temperatures as 200 °C and 250 °C (equivalent to 0.52Tm and 0.57Tm, respectively, where Tm is the melting point of the alloy). The HPT-processed samples for 3 revolutions exhibited superplastic elongations of 640% and 510% at 250 °C with initial strain rates of 2.0 × 10-3 s-1 and 2.0 × 10-2 s-1, respectively.

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Effect of Different Initial Lamellar Plate Thicknesses on Grain Refinement and Superplastic Behaviour in HPT-Processed Ti-6Al-4V Alloy

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.385.182 ◽

2018 ◽

Vol 385 ◽

pp. 182-188

Author(s):

Yi Huang ◽

Jessica Muzy ◽

Piotr Bazarnik ◽

Małgorzata Lewandowska ◽

Terence G. Langdon

Keyword(s):

High Pressure ◽

Lamellar Structure ◽

Room Temperature ◽

High Pressure Torsion ◽

Phase Transformation Temperature ◽

Air Cooling ◽

Microstructure Development ◽

Superplastic Behaviour ◽

Β Phase ◽

Heat Treated

Ti-6Al-4V alloy was heated to above the β phase transformation temperature with two different cooling speeds: air cooling and furnace cooling, in order to generate a full thin lamellar structure and a fully coarse lamellar structure, respectively. Then the alloy in two heat-treated conditions was processed at room temperature up to 10 turns by high-pressure torsion (HPT) processing. Investigations were carried out to study the effect of the different initial lamellar plate thicknesses on the microstructure development during HPT processing, and the corresponding superplastic behaviour at the selected low testing temperatures of 773 - 923 K.

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Mechanical Behavior of a Metal Matrix Nanocomposite Synthesized by High-Pressure Torsion via Diffusion Bonding

Materials Science Forum ◽

10.4028/www.scientific.net/msf.879.1068 ◽

2016 ◽

Vol 879 ◽

pp. 1068-1073

Author(s):

Han Joo Lee ◽

Jae Kyung Han ◽

Byung Min Ahn ◽

Megumi Kawasaki ◽

Terence G. Langdon

Keyword(s):

Mechanical Properties ◽

High Pressure ◽

Metal Matrix ◽

Room Temperature ◽

High Pressure Torsion ◽

Ambient Temperatures ◽

Metal Matrix Nanocomposite ◽

Wide Range ◽

Zk60 Magnesium Alloy ◽

Matrix Nanocomposite

High-pressure torsion (HPT) is one of the major severe plastic deformation (SPD) procedures where disk metals generally achieve exceptional grain refinement at ambient temperatures. HPT has been applied for the consolidation of metallic powders and bonding of machining chips whereas very limited reports examined the application of HPT for the fabrication of nanocomposites. An investigation was initiated to evaluate the potential for the formation of a metal matrix nanocomposite (MMNC) by processing two commercial metal disks of Al-1050 and ZK60 magnesium alloy through HPT at room temperature. Evolutions in microstructure and mechanical properties including hardness and plasticity were examined in the processed disks with increasing numbers of HPT turns up to 5. This study demonstrates the promising possibility for using HPT to fabricate a wide range of hybrid MMNCs from simple metals.

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Texture Evolution of Magnesium Single Crystals Deformed by High-Pressure Torsion

Materials Science Forum ◽

10.4028/www.scientific.net/msf.584-586.263 ◽

2008 ◽

Vol 584-586 ◽

pp. 263-268 ◽

Cited By ~ 8

Author(s):

Bartlomiej J. Bonarski ◽

Erhard Schafler ◽

Borys Mikułowski ◽

Michael Zehetbauer

Keyword(s):

High Pressure ◽

Single Crystals ◽

Room Temperature ◽

High Pressure Torsion ◽

Texture Evolution ◽

In Situ Stress ◽

Higher Symmetry ◽

Strain Measurements ◽

X Ray

Single crystals of technical purity Magnesium (99.8 wt.%) of initial orientations [ ] 2 1 10 and [ ] 2 2 11 were subjected to HPT deformation at room temperature up to strains of 10. The microstructural evolution has been analyzed by X-ray microtexture investigations and by in-situ stress-strain measurements. The results can be described in terms of shear arising from HPT deformation and - with higher strains - in terms of recrystallization. In crystals with hard orientation[ ] 2 2 11 , these features occur at smaller strains than in crystals with soft orientation [ ] 2 1 10 , i.e. with higher symmetry. In general, the observed textures and strength variations are much stronger than those reported for fcc HPT deformed metals.

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