Construction of Processing Map for Biomedical Co-29Cr-6Mo-0.23C-0.14N Alloy by Using Compression Tests

Abstract

The high-temperature deformation behavior of Co-29Cr-6Mo-0.23C-0.14N alloy was investigated by carrying out compression tests; the tests were carried out in the temperature range of 1000-1200 C and strain rates ranging from 0.01 to 30 s À1 with a height reduction of approximately 65%. The optimum hot-working conditions were determined from the processing map based on the dynamic materials model. Dynamic recrystallization was observed to occur over the entire temperature and strain rate range. However, uniformly sized grains were formed for strain rates higher than 1 s À1 , which is considered to be the optimum hot-working condition. In addition, authors suggested that in extremely low stacking fault energy alloy, explosive and homogeneous formation of mechanical twinning should be considered to be stable state, and new processing map with more detailed description of deformation mechanism seems necessary in future.

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

“…This allowed for a reduction in the nickel content, which had been previously believed to be necessary to maintain ductility in CCM alloys, to an extremely low level sufficient to avoid allergic reactions due to nickel ions. The addition of nitrogen was also found to be effective for high-carbon CCM alloy [38,39], and so the generally accepted categories of high/ low carbon and wrought/cast are not necessarily adequate for classifying the materials used for MoM hip implants.…”

Microstructures Behavior in Biomedical Co-Cr-Mo-C-Si-Mn Alloys Containing Nitrogen

“…In recent years, nitrogen has been attracting attention as an effective alloying element for improving the mechanical properties and workability of Co-Cr-Mo alloys [7]. Several authors have studied the microstructures formed in Co-Cr-Mo alloys with nitrogen content [8]. However, the phase formation/dissolution of the secondary phases was not fully understood in those Co-Cr-Mo-C-N alloys.…”