scholarly journals High-pressure torsion-induced phase transformations and grain refinement in Al/Ti composites

2017 ◽  
Vol 52 (20) ◽  
pp. 12170-12184 ◽  
Author(s):  
Y. Sun ◽  
M. Aindow ◽  
R. J. Hebert ◽  
T. G. Langdon ◽  
E. J. Lavernia
Keyword(s):  
High Pressure ◽  
Phase Transformations ◽  
Grain Refinement ◽  
High Pressure Torsion

scholarly journals Omega Phase Formation in Ti–3wt.%Nb Alloy Induced by High-Pressure Torsion

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2262
Author(s):  
Anna Korneva ◽  
Boris Straumal ◽  
Askar Kilmametov ◽  
Alena Gornakova ◽  
Anna Wierzbicka-Miernik ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Phase Transformations ◽  
Grain Refinement ◽  
High Pressure Torsion ◽  
Β Phase ◽  
Ω Phase ◽  
Α Phase ◽  
Transmission Electron ◽  
Different Temperatures

It is well known that severe plastic deformation not only leads to strong grain refinement and material strengthening but also can drive phase transformations. A study of the fundamentals of α → ω phase transformations induced by high-pressure torsion (HPT) in Ti–Nb-based alloys is presented in the current work. Before HPT, a Ti–3wt.%Nb alloy was annealed at two different temperatures in order to obtain the α-phase state with different amounts of niobium. X-ray diffraction analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied for the characterisation of phase transitions and evolution of the microstructure. A small amount of the β-phase was found in the initial states, which completely transformed into the ω-phase during the HPT process. During HPT, strong grain refinement in the α-phase took place, as did partial transformation of the α- into the ω-phase. Therefore, two kinds of ω-phase, each with different chemical composition, were obtained after HPT. The first one was formed from the β-phase, enriched in Nb, and the second one from the α-phase. It was also found that the transformation of the α-phase into the ω-phase depended on the Nb concentration in the α-Ti phase. The less Nb there was in the α-phase, the more of the α-phase was transformed into the ω-phase.

GRAIN REFINEMENT AND MICROSTRUCTURE EVOLUTION IN ALUMINUM A2618 ALLOY BY HIGH-PRESSURE TORSION

2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
Intan Fadhlina Mohamed ◽  
Seungwon Lee ◽  
Kaveh Edalati ◽  
Zenji Horita ◽  
Shahrum Abdullah ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Grain Refinement ◽  
Room Temperature ◽  
Rotation Speed ◽  
High Pressure Torsion ◽  
Applied Pressure ◽  
Saturation Level ◽  
Microstructural Refinement ◽  
Average Grain Size

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.

Phase Transformations in MgH 2 –TiH 2 Hydrogen Storage System by High‐Pressure Torsion Process

2019 ◽  
Vol 22 (1) ◽  
pp. 1900027 ◽  
Author(s):  
Kouki Kitabayashi ◽  
Kaveh Edalati ◽  
Hai‐Wen Li ◽  
Etsuo Akiba ◽  
Zenji Horita
Keyword(s):  
High Pressure ◽  
Hydrogen Storage ◽  
Phase Transformations ◽  
High Pressure Torsion ◽  
Storage System ◽  
Hydrogen Storage System

Phase transformations in a Cu Cr alloy induced by high pressure torsion

2016 ◽  
Vol 114 ◽  
pp. 151-156 ◽  
Author(s):  
Anna Korneva ◽  
Boris Straumal ◽  
Askar Kilmametov ◽  
Robert Chulist ◽  
Piotr Straumal ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transformations ◽  
High Pressure Torsion

scholarly journals Plastic Deformation of BaTiO3Ceramics by High-pressure Torsion and Changes in Phase Transformations, Optical and Dielectric Properties

2015 ◽  
Vol 3 (4) ◽  
pp. 216-221 ◽  
Author(s):  
Kaveh Edalati ◽  
Masashi Arimura ◽  
Yoshifumi Ikoma ◽  
Takeshi Daio ◽  
Moriji Miyata ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Dielectric Properties ◽  
Phase Transformations ◽  
High Pressure Torsion
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