Effect of single-crystal orientation on the molybdenum structure and hardness upon high pressure torsion

2021 ◽  
pp. 105754
Author(s):  
L.M. Voronova ◽  
T.I. Chashchukhina ◽  
T.M. Gapontseva ◽  
A.M. Patselov ◽  
V.P. Pilyugin ◽  
...  
Keyword(s):  
High Pressure ◽  
Single Crystal ◽  
Crystal Orientation ◽  
High Pressure Torsion

Effect of High Pressure Torsion on Crystal Orientation to Improve the Thermoelectric Property of a Bi2Te3-Based Thermoelectric Semiconductor

2010 ◽  
Vol 89-91 ◽  
pp. 41-46 ◽  
Author(s):  
Maki Ashida ◽  
Takashi Hamachiyo ◽  
Kazuhiro Hasezaki ◽  
Hirotaka Matsunoshita ◽  
Z. Horita
Keyword(s):  
High Pressure ◽  
Power Factor ◽  
Crystal Orientation ◽  
High Pressure Torsion ◽  
Preferred Orientation ◽  
Orientation Factor ◽  
X Ray Diffraction ◽  
Fine Grain ◽  
Maximum Value ◽  
P Type

A Bi2Te3-based thermoelectric semiconductor was subjected by high pressure torsion (HPT). Sample disks of p-type Bi0.5Sb1.5Te3.0 were cut from sintered compacts that were made by mechanically alloying (MA) followed by hot pressing. Disks were subjected by HPT with 1, 5 and 10 turns at 473 K under 6.0 GPa of pressure. Crystal orientation was investigated by X-ray diffraction. Microstructures were characterized using scanning electron microscopy. Results indicated that HPT disks after 5 turns had a preferred orientation and a fine grain compared with pre-HPT disks while the orientation factor was decreased after HPT using 10 turns. The power factor had a maximum value at 5 turns as determined by measuring its thermoelectric properties. A maximum power factor of 4.30×10-3 Wm-1K-2 was obtained for HPT disks after 5 turns. This value was larger than that for the pre-HPT disk. The over-HPT of 10 turns was found to have caused a decrease in the preferred orientation leading to a low power factor.

scholarly journals Effects of Low Rotational Speed on Crystal Orientation of Bi2Te3-Based Thermoelectric Semiconductors Deformed by High-Pressure Torsion

2012 ◽  
Vol 53 (4) ◽  
pp. 588-591 ◽  
Author(s):  
Maki Ashida ◽  
Natsuki Sumida ◽  
Kazuhiro Hasezaki ◽  
Hirotaka Matsunoshita ◽  
Zenji Horita
Keyword(s):  
High Pressure ◽  
Rotational Speed ◽  
Crystal Orientation ◽  
High Pressure Torsion

Control of Crystallographic Orientation and Grain Refinement in Bi2Te3-Based Thermoelectric Semiconductors by Applying High Pressure Torsion

2008 ◽  
Vol 584-586 ◽  
pp. 1006-1011 ◽  
Author(s):  
Maki Ashida ◽  
Takashi Hamachiyo ◽  
Kazuhiro Hasezaki ◽  
Hirotaka Matsunoshita ◽  
Masaaki Kai ◽  
...  
Keyword(s):  
High Pressure ◽  
Crystal Orientation ◽  
High Pressure Torsion ◽  
Crystallographic Structure ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Refined Microstructure ◽  
Vertical Bridgman ◽  
P Type

Prepared were p-type Bi2Te3-based thermoelectric semiconductors, having a grain-refined microstructure and a preferred orientation of anisotropic crystallographic structure. Disks with a nominal composition Bi0.5Sb1.5Te3.0 were cut from an ingot grown by the vertical Bridgman method (VBM) and deformed at 473 K under a pressure of 6.0 GPa by high pressure torsion (HPT). The crystal orientation was characterized with X-ray diffraction. The microstructures were characterized by using optical microscopy and scanning electron microscopy. It was found that the HPT disks had a fine and preferentially oriented grain compared to that of the VBM disks. Further, the power factor of the HPT disks was about twice as large as that of the VBM disks. These results indicate that HPT is effective for improving the thermoelectric properties of Bi2Te3-based thermoelectric semiconductors.

A study on the texture evolution mechanism of nickel single crystal deformed by high pressure torsion

2017 ◽  
Vol 684 ◽  
pp. 239-248 ◽  
Author(s):  
Peitang Wei ◽  
Cheng Lu ◽  
Kiet Tieu ◽  
Lihong Su ◽  
Guanyu Deng ◽  
...  
Keyword(s):  
High Pressure ◽  
Single Crystal ◽  
High Pressure Torsion ◽  
Texture Evolution ◽  
Evolution Mechanism ◽  
Nickel Single Crystal

Evolution of the structure of an α-titanium single crystal during high-pressure torsion

2015 ◽  
Vol 60 (7) ◽  
pp. 1005-1013 ◽  
Author(s):  
Yu. V. Khlebnikova ◽  
L. Yu. Egorova ◽  
V. P. Pilyugin ◽  
T. R. Suaridze ◽  
A. M. Patselov
Keyword(s):  
High Pressure ◽  
Single Crystal ◽  
High Pressure Torsion

scholarly journals Investigation of Grain Refinement Mechanism of Nickel Single Crystal during High Pressure Torsion by Crystal Plasticity Modeling

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 351
Author(s):  
Peitang Wei ◽  
Hao Zhou ◽  
Huaiju Liu ◽  
Caichao Zhu ◽  
Wei Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Single Crystal ◽  
Grain Refinement ◽  
Crystal Plasticity ◽  
High Pressure Torsion ◽  
Lattice Rotation ◽  
Deformation Method ◽  
Fine Grained ◽  
Nickel Single Crystal ◽  
Refinement Mechanism

The excellent properties of ultra-fine grained (UFG) materials are relevant to substantial grain refinement and the corresponding induced small grains delineated by high-angle grain boundaries. The present study aims to understand the grain refinement mechanism by examining the nickel single crystal processed by high pressure torsion (HPT), a severe plastic deformation method to produce UFG materials based upon crystal plasticity finite element (CPFEM) simulations. The predicted grain maps by the developed CPFEM model are capable of capturing the prominent characteristics associated with grain refinement in HPT. The evolution of the orientation of structural elements and the rotations of crystal lattices during the HPT process of the detected differently oriented grains are extensively examined. It has been found that there are mainly two intrinsic origins of lattice rotation which cause the initial single crystal to subdivide. The correlation between the crystallographic orientation changes and lattice rotations with the grain fragmentation are analyzed and discussed in detail based on the theory of crystal plasticity.

Single Crystal Growth of High-Pressure Phases of Ice and Salt Hydrate Far Below the Original Melting Point by Mixing Alcohol: Crystal Structure Determination of Magnesium Chloride Heptahydrate

2020 ◽  
Author(s):  
Keishiro Yamashita ◽  
Kazuki Komatsu ◽  
Hiroyuki Kagi
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Crystal Growth ◽  
Single Crystal ◽  
Room Temperature ◽  
Growth Technique ◽  
Salt Hydrate ◽  
X Ray

An crystal-growth technique for single crystal x-ray structure analysis of high-pressure forms of hydrogen-bonded crystals is proposed. We used alcohol mixture (methanol: ethanol = 4:1 in volumetric ratio), which is a widely used pressure transmitting medium, inhibiting the nucleation and growth of unwanted crystals. In this paper, two kinds of single crystals which have not been obtained using a conventional experimental technique were obtained using this technique: ice VI at 1.99 GPa and MgCl<sub>2</sub>·7H<sub>2</sub>O at 2.50 GPa at room temperature. Here we first report the crystal structure of MgCl2·7H2O. This technique simultaneously meets the requirement of hydrostaticity for high-pressure experiments and has feasibility for further in-situ measurements.

Intermixing of Fe and Cu on the Atomic Scale by High-Pressure Torsion as Revealed by Dc- and Ac-Squid Susceptometry

2020 ◽  
Author(s):  
Martin Stückler ◽  
Heinz Krenn ◽  
Lukas Weissitsch ◽  
Stefan Wurster ◽  
Reinhard Pippan ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Atomic Scale
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