Ring-Constraint High-Pressure Torsion Process

Soo Hyun Joo, Hyoung Seop Kim

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


In this study, a constraint ring around a workpiece was employed in order to develop back pressure in addition to a compressive die pressure in high-pressure torsion (HPT) process. The influence of the constraint ring during the HPT process was analyzed using the finite element method and experimental analyses. Greater back pressure was developed when a ring of a stronger material enveloped the workpiece. In the experiments, fracture of a brittle material [e.g., La-based bulk metallic glass (BMG)], was limited even at large shear strain (~315) during the ring-constraint HPT (RC-HPT) process due to reduced tensile stress at the edge of the deforming BMG workpiece. Furthermore, the RC-HPT process had beneficial effects on powder consolidation and bonding. The RC-HPT process exhibited smaller loss of material than did the conventional semi-constrained HPT process. The Cu disk produced by the powder RC-HPT had smaller grain sizes because back pressure generated more dislocations and finer grain size in the Cu workpiece.

Original languageEnglish
Pages (from-to)3473-3478
Number of pages6
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Issue number7
Publication statusPublished - 2016 Jul 1

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys


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