Uneven damage on head and liner contact surfaces of a retrieved Co-Cr-based metal-on-metal hip joint bearing: An important reason for the high failure rate

Yuichiro Koizumi, Yan Chen, Yunping Li, Kenta Yamanaka, Akihiko Chiba, Shun Ichiro Tanaka, Yoshihiro Hagiwara

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Detailed metallurgical investigations have been performed on a used Co-Cr-based metal-on-metal (MoM) hip joint bearing containing a type of liner that is commonly used in such joints. The damage on the metal-liner sliding surface was considerably more severe than that on the metal head counterpart, in terms of wear-scar density and width and microcrack frequency. Cross-sectional transmission electron microscopy revealed that a thick (> 3 μm) nanocrystalline layer formed on the sliding surface of the head, whereas the liner had coarse carbides embedded in it and nanocrystals were formed in a very limited region no deeper than 1 μm. Comparative investigation of an unused head and a liner of identical type showed that although the chemical compositions of the liner and head were nearly identical, their microstructures were significantly different. Specifically, the grain size in the liner was larger than that in the head on average, and the grain boundaries of the liner were decorated with coarse carbides. Moreover, X-ray diffraction analysis revealed a large tensile residual stress only in the liner. These differences are possibly responsible for the wear damage on the liner being more serious than that on the head.

Original languageEnglish
Pages (from-to)532-543
Number of pages12
JournalMaterials Science and Engineering C
Volume62
DOIs
Publication statusPublished - 2016 May 1

Keywords

  • Chemical composition
  • Co-Cr alloy
  • Hip prosthesis
  • Surface analysis

ASJC Scopus subject areas

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

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