Real hydrostatic pressure in high-pressure torsion measured by bismuth phase transformations and FEM simulations

Kaveh Edalati, Dong Jun Lee, Takashi Nagaoka, Makoto Arita, Hyoung Seop Kim, Zenji Horita, Reinhard Pippan

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Hydrostatic pressure is a significant parameter influencing the evolution of microstructure and phase transformations in the high-pressure torsion (HPT) process. Currently, there are significant arguments relating to the magnitude of the real hydrostatic pressure during the process. In this study, phase transformations in bismuth, copper and titanium combined with the finite element method (FEM) were employed to determine the real pressure in processing disc samples by HPT. Any break in the variation of steady-state hardness (monitored experimentally by in-situ torque and temperature rise measurements) versus pressure was considered as a phase transition. FEM simulations show that the hydrostatic pressure is reasonably isotropic but decreases with increasing distance from the disc center and remains unchanged across the disc thickness. Both experiments and simulations indicate that the mean hydrostatic pressure during HPT processing closely corresponds to the compressive load over the disc area plus the contact area between the anvils.

Original languageEnglish
Pages (from-to)533-538
Number of pages6
JournalMaterials Transactions
Volume57
Issue number4
DOIs
Publication statusPublished - Jan 1 2016

Fingerprint

Bismuth
Hydrostatic pressure
hydrostatic pressure
Torsional stress
bismuth
torsion
phase transformations
finite element method
Phase transitions
Finite element method
simulation
anvils
temperature measurement
torque
Processing
Titanium
hardness
titanium
Temperature measurement
Copper

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Real hydrostatic pressure in high-pressure torsion measured by bismuth phase transformations and FEM simulations. / Edalati, Kaveh; Lee, Dong Jun; Nagaoka, Takashi; Arita, Makoto; Kim, Hyoung Seop; Horita, Zenji; Pippan, Reinhard.

In: Materials Transactions, Vol. 57, No. 4, 01.01.2016, p. 533-538.

Research output: Contribution to journalArticle

Edalati, Kaveh ; Lee, Dong Jun ; Nagaoka, Takashi ; Arita, Makoto ; Kim, Hyoung Seop ; Horita, Zenji ; Pippan, Reinhard. / Real hydrostatic pressure in high-pressure torsion measured by bismuth phase transformations and FEM simulations. In: Materials Transactions. 2016 ; Vol. 57, No. 4. pp. 533-538.
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