Microstructure development of ultra fine grained Mg-22 wt%Gd alloy prepared by high pressure torsion

Mg-Tb-Nd ternary alloy represents a novel hardenable Mg-based alloy with enhanced strength and favorable creep properties. In the present work we studied microstructure of ultra fine grained (UFG) Mg-Tb-Nd alloy prepared by high pressure torsion (HPT). Lattice defects introduced into the specimen by the severe plastic deformation play a key role in physical properties of UFG specimens. It is known that positron lifetime (PL) spectroscopy is highly sensitive to open volume defects (like vacancies, dislocations, etc.). Therefore, PL spectroscopy is an ideal tool for defect characterizations in the HPT deformed specimens. In the present work we combined PL studies with transmission electron microscopy and microhardness measurements. After detailed characterization of the as-deformed structure, the specimens were step-by-step isochronally annealed and we investigated the development of microstructure with increasing temperature.

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Spatial distribution of defects in ultra-fine grained copper prepared by high-pressure torsion

phys stat sol (a) ◽

10.1002/pssa.200305929 ◽

2003 ◽

Vol 195 (2) ◽

pp. 335-349 ◽

Cited By ~ 14

Author(s):

Jakub Čížek ◽

Ivan Procházka ◽

Gerhard Brauer ◽

Wolfgang Anwand ◽

Radomír Kužel ◽

...

Keyword(s):

High Pressure ◽

Spatial Distribution ◽

High Pressure Torsion ◽

Fine Grained

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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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Recrystallization and Grain Growth in Ultra Fine Grained Materials Produced by High Pressure Torsion

Materials Science Forum ◽

10.4028/www.scientific.net/msf.715-716.373 ◽

2012 ◽

Vol 715-716 ◽

pp. 373-373

Author(s):

Anahita Khorashadizadeh ◽

Myrjam Winning ◽

Stefan Zaefferer ◽

Dierk Raabe

Keyword(s):

Mechanical Properties ◽

Plastic Deformation ◽

High Pressure ◽

Severe Plastic Deformation ◽

Grain Growth ◽

High Pressure Torsion ◽

Fine Grained ◽

Fine Grained Material

Investigations of the microstructure of materials processed via severe plastic deformation methods such as high pressure torsion (HPT) and their recrystallization behaviour is of great interest as they are capable of producing ultra fine grained material (UFD) with good mechanical properties.

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