Precipitates in biomedical Co-Cr-Mo-C-Si-Mn alloys

T. Narushima, Alfirano, S. Mineta, S. Namba, T. Yoneda, K. Ueda

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

11 Citations (Scopus)


The phase and dissolution behavior of precipitates in biomedical ASTM F75 Co-Cr-Mo-C-Si-Mn alloys were investigated. Alloys of five different compositions, Co-28Cr-6Mo-0.25C-1Si, Co-28Cr-6Mo-0.25C-1Mn, Co-28Cr-6Mo-0.25C- 1Si-1Mn, Co-28Cr-6Mo-0.15C-1Si, and Co-28Cr-6Mo-0.35C-1Si, were heat-treated from 1448 to 1548 K. The precipitates observed in the as-cast and heat-treated alloys were carbides (M23C6 type, η-phase, and π-phase) and an intermetallic compound (χ-phase). The main precipitates observed after heat treatment at high temperatures such as 1548 K were π-phase and M23C6 type carbide. At these high temperatures, two types of starlike precipitates-dense and stripe-patterned-were observed. The starlike-dense precipitate was the π-phase, and the starlike precipitate with a stripe pattern was identified as the M23C 6 type carbide and metallic fcc γ-phase. In the alloys heat-treated at 1448 to 1498 K, blocky-dense M23C6 type carbide was primarily observed. χ-phase was detected in the Co-28Cr-6Mo-0.15C-1Si alloy under as-cast condition and after heat treatment at 1448-1523 K for a short holding time. The addition of Si seemed to increase the holding time for complete precipitate dissolution because of the effects of Si on the promotion of π-phase formation at high temperatures and the increased carbon activity in the metallic matrix.

Original languageEnglish
Title of host publicationAdvanced Materials Research QiR 12
Number of pages8
Publication statusPublished - 2011
Event12th International Conference on Quality in Research, QiR 2011 - Bali, Indonesia
Duration: 2011 Jul 42011 Jul 7

Publication series

NameAdvanced Materials Research
ISSN (Print)1022-6680


Conference12th International Conference on Quality in Research, QiR 2011


  • π-phase
  • χ-phase
  • Carbide
  • Co-Cr-Mo alloy
  • Heat treatment
  • Microstructure


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