Effect of the High-Pressure Torsion (HPT) and Subsequent Isothermal Annealing on the Phase Transformation in Biomedical Ti15Mo Alloy

Ti15Mo metastable beta Ti alloy was solution treated and subsequently deformed by high-pressure torsion (HPT). HPT-deformed and benchmark non-deformed solution-treated materials were annealed at 400 °C and 500 °C in order to investigate the effect of UFG microstructure on the α-phase precipitation. Phase evolution was examined using laboratory X-ray diffraction (XRD) and by high-energy synchrotron X-ray diffraction (HEXRD), which provided more accurate measurements. Microstructure was observed by scanning electron microscopy (SEM) and microhardness was measured for all conditions. HPT deformation was found to significantly enhance the α phase precipitation due the introduction of lattice defects such as dislocations or grain boundaries, which act as preferential nucleation sites. Moreover, in HPT-deformed material, α precipitates are small and equiaxed, contrary to the α lamellae in the non-deformed material. ω phase formation is suppressed due to massive α precipitation and consequent element partitioning. Despite that, HPT-deformed material after ageing exhibits the high microhardness exceeding 450 HV.

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Gradient residual strain and stress distributions in a high pressure torsion deformed iron disk revealed by high energy X-ray diffraction

Scripta Materialia ◽

10.1016/j.scriptamat.2017.11.037 ◽

2018 ◽

Vol 146 ◽

pp. 178-181 ◽

Cited By ~ 8

Author(s):

J. Todt ◽

J. Keckes ◽

G. Winter ◽

P. Staron ◽

A. Hohenwarter

Keyword(s):

High Pressure ◽

Residual Strain ◽

High Pressure Torsion ◽

High Energy ◽

Stress Distributions ◽

X Ray Diffraction ◽

X Ray

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A perforated diamond anvil cell for high-energy x-ray diffraction of liquids and amorphous solids at high pressure

Review of Scientific Instruments ◽

10.1063/1.3356977 ◽

2010 ◽

Vol 81 (3) ◽

pp. 035110 ◽

Cited By ~ 27

Author(s):

Emmanuel Soignard ◽

Chris J. Benmore ◽

Jeffery L. Yarger

Keyword(s):

High Pressure ◽

Diamond Anvil Cell ◽

Amorphous Solids ◽

High Energy ◽

X Ray Diffraction ◽

X Ray ◽

Diamond Anvil

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Phase Constitution and Heat Treatment Behavior of Zr-Nb Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.561-565.1435 ◽

2007 ◽

Vol 561-565 ◽

pp. 1435-1440 ◽

Cited By ~ 2

Author(s):

Masahiko Ikeda ◽

Tsuyoshi Miyazaki ◽

Satoshi Doi ◽

Michiharu Ogawa

Keyword(s):

Heat Treatment ◽

Elastic Modulus ◽

Elastic Moduli ◽

X Ray Diffraction ◽

Phase Constitution ◽

X Ray ◽

Β Phase ◽

Ω Phase ◽

Solution Treated ◽

Α Phase

Phase constitution in the solution-treated and quenched state and the heat treatment behavior were investigated by electrical resistivity, hardness, and elastic modulus measurements, X-ray diffraction, and optical microscopy. Hexagonal martensite and the β phase were identified in the Zr-5mass%Nb alloy. β and ω phases were identified in the Zr-10 and 15mass%Nb alloys, and only the β phase was identified in the Ti-20Nb alloy. Resistivity at RT, Vickers hardness and elastic modulus increased up to 10Nb and then decreased dramatically at 15Nb. Above 15Nb, these values slightly decreased. The elastic moduli for 15Nb and 20Nb were 59.5 and 55.5 GPa, respectively. On isochronal heat treatment, the isothermal ω phase precipitated between 473 and 623 K and then the α phase precipitated in the 10Nb, 15Nb and 20Nb alloys.

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Effect of Heat Treatment on Microstructure and Mechanical Properties of Ti-13Nb-13Zr Alloy Produced by Powder Metallurgy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.802.457 ◽

2014 ◽

Vol 802 ◽

pp. 457-461 ◽

Cited By ~ 1

Author(s):

José Hélio Duvaizem ◽

N.M.F. Mendes ◽

J.C.S. Casini ◽

A.H. Bressiani ◽

H. Takiishi

Keyword(s):

Heat Treatment ◽

Elastic Modulus ◽

Powder Metallurgy ◽

Phase Precipitation ◽

X Ray Diffraction ◽

Dynamic Mechanical Analyzer ◽

X Ray ◽

Α Phase ◽

13Zr Alloy ◽

Scanning Electron

Ti-13Nb-13Zr alloy produced via powder metallurgy was submitted to heat treatment under various conditions and the effects on microstructure and elastic modulus were investigated. Heat treatment was performed using temperatures above and below α/β transus combined with different cooling rates – furnace cooling and water quenching. Microstructure and phases were analyzed employing scanning electron microscopy and X-ray diffraction. Elastic Modulus was determined using a dynamic mechanical analyzer (DMA). The results indicated that α phase precipitation and elastic modulus values increased after heat treatment performed using temperature below α/β transus. However, when it was performed above α/β transus and using higher cooling rate, a decrease in elastic modulus was observed despite higher α phase precipitation, indicating that the microstructural modifications observed via SEM, due to the presence of martensitic α phase, influenced on elastic modulus values.

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Femtosecond Laser Synthesis of the High-Pressure Phase of Iron

Materials Science Forum ◽

10.4028/www.scientific.net/msf.512.349 ◽

2006 ◽

Vol 512 ◽

pp. 349-354

Author(s):

Tomokazu Sano ◽

Osamu Sakata ◽

Etsuji Ohmura ◽

Isamu Miyamoto ◽

Akio Hirose ◽

...

Keyword(s):

Shock Wave ◽

High Pressure ◽

Femtosecond Laser ◽

X Ray Diffraction ◽

X Ray ◽

Α Phase ◽

Iron Sample ◽

Ε Phase ◽

Pressure Phase ◽

Fcc Structure

The synthesis of the high-pressure ε phase of iron, which has not been observed under a conventional shock compression, was attained using a femtosecond laser. The lower pressure and temperature α phase (bcc) transforms to the γ phase (fcc) at higher temperatures and to the ε phase (hcp) at higher pressures. A shock induced α to ε phase transition in iron is one of the most famous transitions under high pressure. The induced high-pressure ε phase by a conventional shock loading returns to the α phase and it is not quenched after the shock release because this transition is considered to be diffusionless. Crystalline structures in a recovered iron sample after the femtosecond laser (800 nm, 120 fs, 1014 W/cm2) irradiation were determined using the electron diffraction and the synchrotron X-ray diffraction methods. These results show the existence of the ε phase and the fcc structure in the recovered iron. The femtosecond laser-driven shock wave may have the potential to synthesis high-pressure phases of other materials that has not been done using the conventional shock wave.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.584-586.1006 ◽

2008 ◽

Vol 584-586 ◽

pp. 1006-1011 ◽

Cited By ~ 10

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.

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Crystal structure of the high pressure phases of bismuth bi iii and bi iii′ by high energy synchrotron x-ray diffraction

High Pressure Research ◽

10.1080/08957959608240468 ◽

1996 ◽

Vol 15 (3) ◽

pp. 143-158 ◽

Cited By ~ 23

Author(s):

J. H. Chen ◽

H. Iwasaki ◽

T. Ktkegawa

Keyword(s):

Crystal Structure ◽

High Pressure ◽

High Energy ◽

X Ray Diffraction ◽

X Ray

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

Metals ◽

10.3390/met11040573 ◽

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.

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Peculiarities in the Texture Formation of Intermetallic Compounds Deformed by High Pressure Torsion

MRS Proceedings ◽

10.1557/opl.2014.963 ◽

2014 ◽

Vol 1760 ◽

Cited By ~ 1

Author(s):

Christine Tränkner ◽

Aurimas Pukenas ◽

Jelena Horky ◽

Michael Zehetbauer ◽

Werner Skrotzki

Keyword(s):

High Pressure ◽

High Pressure Torsion ◽

Electron Backscatter Diffraction ◽

High Energy ◽

X Ray ◽

Local Texture ◽

Large Rotations ◽

Electron Backscatter ◽

Shear Strains ◽

Backscatter Diffraction

ABSTRACTNiAl, YCu and TiAl polycrystals with B2 and L10 structure, respectively, have been deformed by high pressure torsion (HPT) at temperatures between 20°C and 500°C at a hydrostatic pressure of 8 GPa to high shear strains. Local texture measurements were done by diffraction of high-energy synchrotron radiation and X-ray microdiffraction. In addition, the microstructure was analyzed by electron backscatter diffraction (EBSD). Besides typical shear components an oblique cube component is observed with quite large rotations about the transverse direction. Based on the temperature dependence of this component as well as on microstructure investigations it is concluded that it is formed by discontinuous dynamic recrystallization. The influence of high pressure on recrystallization of intermetallics at low temperatures is discussed.

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