Deformation-induced martensitic transformation in Co-28Cr-6Mo alloy produced by laser powder bed fusion: Comparison surface vs. bulk

Luiz H. M. Antunes, John Jairo Hoyos, Tathiane Caminha Andrade, Paulo Willian C. Sarvezuk, L. Wu, Julian A. Ávila, João Pedro Oliveira, Norbert Schell, A. L. Jardini, Jaroslava Žilková, Paula F. da Silva Farina, Hamilton Ferreira Gomes Abreu, Miloslav Béreš

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

The wear resistance of the biomedical low-carbon Co-28Cr-6Mo (wt.-%) alloy is primarily determined by the onset and magnitude of the face-centered cubic to hexagonal close-packed deformation-induced martensitic phase transformation. In metal-on-metal joint bearings, local plastic deformation occurs on the surface and in the subsurface regions. This can cause deformation-assisted structural changes in the material, such as mechanical twinning and/or martensitic transformation. In the present work, we report the structural transition on the surface and bulk of a laser powder bed fusion additively manufactured Co-28Cr-6Mo alloy in response to an externally imposed load. This study was possible using in-situ synchrotron X-ray diffraction at two different energy levels. Our results revealed that from tensile deformation to fracture, the phase transformation kinetics and magnitude were marginally higher on the surface. During transformation, {200}FCC peak broadening was observed in the bulk and this was attributed to stacking fault accumulation.

Original languageEnglish
Article number102100
JournalAdditive Manufacturing
Volume46
DOIs
Publication statusPublished - Oct 2021

Keywords

  • CoCrMo alloy
  • in-situ synchrotron X-ray diffraction
  • Martensitic phase transformation
  • Peak broadening
  • Variant selection

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