scholarly journals Investigation on micro-hardness with shear strain extent for copper specimens subjected to high pressure torsion

2008 ◽  
Author(s):  
Yuan Liu ◽  
Youshi Hong ◽  
Keke Fan ◽  
Xiaodong Ji
Keyword(s):  
High Pressure ◽  
Shear Strain ◽  
High Pressure Torsion ◽  
Micro Hardness

scholarly journals Slippage during high-pressure torsion of commercially pure titanium and application of accumulative HPT to it

2022 ◽  
Vol 1213 (1) ◽  
pp. 012003
Author(s):  
D V Gunderov ◽  
A A Churakova ◽  
A V Sharafutdinov ◽  
V D Sitdikov ◽  
V V Astanin
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Pure Titanium ◽  
Phase Changes ◽  
Phase Content ◽  
Commercially Pure Titanium ◽  
Micro Hardness ◽  
Ω Phase ◽  
Commercially Pure ◽  
First Time

Abstract A new efficient method was used to find that in the case of high-pressure torsion of commercially pure titanium, accumulation of shear strain in Ti does not occur due to slippage of anvils. Despite this, micro-hardness increases as the number of turns n increases, and Ti structure is refined more intensively. High-pressure torsion is accompanied by a high-pressure ω-phase formation. However, the content of ω-phase changes non-monotonously with an increase in the number of turns. First, while number of turns is less than n=5, the ω-phase content reaches 50%. Upon further deformation, the ω-phase content decreases to 15% for n=20. A new accumulative high-pressure torsion method is applied to commercially pure titanium for the first time. Accumulative high-pressure torsion leads to the strongest transformation of the structure and an increase in hardness, since stronger real deformation occurs due to composition of compression and torsion strain cycles.

Formation of Bulk Nanostructured Al3Ni from Elemental Micropowders Using High-Pressure Torsion

2013 ◽  
Vol 765 ◽  
pp. 378-382 ◽  
Author(s):  
Ali Alhamidi ◽  
Kaveh Edalati ◽  
Zen Ji Horita
Keyword(s):  
High Pressure ◽  
Diffusion Coefficient ◽  
Shear Strain ◽  
Melting Temperature ◽  
High Pressure Torsion ◽  
Processing Temperature ◽  
Powder Mixtures

The formation of bulk nanograined Al3Ni intermetallics from elemental micro-powder mixtures of Al-25 mol.% Ni are studied after processing by high-pressure torsion (HPT) for various turns at 473 K and at 573 K. It is found that nanograined Al3Ni intermetallics with high angles of misorientation are produced at temperatures well below the melting temperature. The fraction of Al3Ni intermetallics increases by increasing the shear strain and increasing the HPT processing temperature. During HPT, both Ni and Al atoms diffuse significantly in each other with a diffusion coefficient well comparable to the atomic interdiffusion in the Al3Ni intermetallic at its melting temperature.

scholarly journals Assessment of homogeneity of the shear-strain pattern in Al–7wt%Si casting alloy processed by high-pressure torsion

2014 ◽  
Vol 597 ◽  
pp. 102-110 ◽  
Author(s):  
C.M. Cepeda-Jiménez ◽  
A. Orozco-Caballero ◽  
J.M. García-Infanta ◽  
A.P. Zhilyaev ◽  
O.A. Ruano ◽  
...  
Keyword(s):  
High Pressure ◽  
Shear Strain ◽  
High Pressure Torsion ◽  
Casting Alloy ◽  
Strain Pattern

Microstructure, Micro‐Hardness, and Corrosion Resistance of Commercial Purity Al Processed by Hollow‐Cone High‐Pressure Torsion

2018 ◽  
Vol 21 (3) ◽  
pp. 1800905 ◽  
Author(s):  
Jing Guo ◽  
Xiaorong Zhang ◽  
Dan Kong ◽  
Soo‐Hyun Joo ◽  
Wooyeol Kim ◽  
...  
Keyword(s):  
High Pressure ◽  
Corrosion Resistance ◽  
High Pressure Torsion ◽  
Commercial Purity ◽  
Micro Hardness ◽  
Hollow Cone

scholarly journals Influence of HPT and Accumulative High-Pressure Torsion on the Structure and Hv of a Zirconium Alloy

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 573
Author(s):  
Dmitry Gunderov ◽  
Andrey Stotskiy ◽  
Yuri Lebedev ◽  
Veta Mukaeva
Keyword(s):  
High Pressure ◽  
Zirconium Alloy ◽  
High Pressure Torsion ◽  
Ti Alloy ◽  
Micro Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ω Phase ◽  
First Time ◽  
Torsion Deformation

The authors previously used the accumulative high-pressure torsion (ACC HPT) method for the first time on steel 316, β-Ti alloy, and bulk metallic glass vit105. On low-alloyed alloys, in particular, the zirconium alloy Zr-1%Nb, the new method was not used. This alloy has a tendency to α → ω phase transformations at using simple HPT. When using ACC HPT, the α → ω transformation can be influenced to a greater extent. This article studies the sliding effect and accumulation of shear strain in Zr-1%Nb alloy at various stages of high-pressure torsion (HPT). The degree of shear deformation at different stages of HPT was estimated. The influence of various high-pressure torsion conditions on the micro-hardness and phase composition by X-ray diffraction (XRD) of Zr-1%Nb was analyzed. It is shown that at high-pressure torsion revolutions of n = 2, anvils and the specimen significantly slip, which is a result of material strengthening. It was found that despite sliding, regular high-pressure torsion resulted in the high strengthening of Zr-1%Nb alloy (micro-hardness more than doubled), and after high-pressure torsion n = 10, up to 97% of the high-pressure ω-phase was formed in it (as in papers of other researchers). Accumulative high-pressure torsion deformation leads to the strongest transformation of the Zr-1%Nb structure and Hv and, therefore, to a higher real strain of the material due to composition by upsetting and torsion in strain cycles.

scholarly journals Hydrolytic Hydrogen Production on Al–Sn–Zn Alloys Processed by High-Pressure Torsion

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1209 ◽  
Author(s):  
Fan Zhang ◽  
Kaveh Edalati ◽  
Makoto Arita ◽  
Zenji Horita
Keyword(s):  
High Pressure ◽  
Hydrogen Production ◽  
Shear Strain ◽  
Pitting Corrosion ◽  
Hydrogen Generation ◽  
High Pressure Torsion ◽  
Generation Rate ◽  
Phase Mixing ◽  
Zn Alloy ◽  
Zn Alloys

Aluminium-tin-based alloys with different compositions were synthesized by a high-pressure torsion (HPT) method. The effect of different alloying elements and processing routes on the hydrogen generation performance of the alloys was investigated. The results show that Zn can enhance the hydrogen generation rate and yield by promoting pitting corrosion. The highest reactivity in water was achieved for an Al-30wt %Sn-10wt %Zn alloy. Detailed analysis of the Al-30wt %Sn-10wt %Zn alloy shows that increasing the shear strain and the resultant formation of ultrafine grains and phase mixing enhance the hydrogen generation rate through the effects of both nanogalvanic cells and pitting corrosion.

A visualization of shear strain in processing by high-pressure torsion

2010 ◽  
Vol 45 (3) ◽  
pp. 765-770 ◽  
Author(s):  
Y. Cao ◽  
Y. B. Wang ◽  
S. N. Alhajeri ◽  
X. Z. Liao ◽  
W. L. Zheng ◽  
...  
Keyword(s):  
High Pressure ◽  
Shear Strain ◽  
High Pressure Torsion

scholarly journals On the Heterogeneity of Local Shear Strain Induced by High‐Pressure Torsion

2019 ◽  
Vol 22 (1) ◽  
pp. 1900477 ◽  
Author(s):  
Wei Jiang ◽  
Hao Zhou ◽  
Yang Cao ◽  
Jinfeng Nie ◽  
Yusheng Li ◽  
...  
Keyword(s):  
High Pressure ◽  
Shear Strain ◽  
High Pressure Torsion ◽  
Local Shear

Cooperative Grain Boundary Sliding and Shear Banding at High Strains in Ultrafine Grained and Nanocrystalline Pd Alloys

2010 ◽  
Vol 667-669 ◽  
pp. 649-656
Author(s):  
Yulia Ivanisenko ◽  
Hans Jörg Fecht
Keyword(s):  
High Pressure ◽  
Grain Boundary ◽  
Shear Strain ◽  
High Pressure Torsion ◽  
Mechanical Test ◽  
Shear Bands ◽  
Grain Boundary Sliding ◽  
Materials Testing ◽  
Ultrafine Grained ◽  
Boundary Sliding

Instrumented high pressure torsion, i.e. mechanical test in a torsion mode under high pressure, allows interesting possibility of materials testing, because materials mechanical response can be studied in a practically unlimited shear strain range. We have studied microstructures formed in initially coarse crystalline and nanocrystalline (nc) Pd and its alloys after instrumented HPT up to shear strain 300, and revealed signatures of similar processes occurring in all these materials. In particular, we found traces of cooperative grain boundary sliding in the form of aligned in parallel segments of boundaries of several grains with straightened triple points. Fracture surfaces contained shear bands. Texture measurements revealed lower dislocation activity in nanocrystalline state as compared with coarse crystalline one. Therefore we argue that cooperative grain boundary sliding is an important deformation mechanism at large strain which develops in both ultrafine grained (ufg) and nanocrystalline materials. In nc and ufg materials planes of cooperative grain boundary sliding act as precursors of shear bands and shear occurs along planes formed by numerous grain boundaries.

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