Dynamic Recrystallization Behavior of Biomedical CCM Alloy with Additions of C and N

Abstract

In order to examine the dynamic recrystallization (DRX) behaviors of Co-29Cr-6Mo alloy with additions of both C and N (hereafter CCMCN alloy), uniaxial compression tests in the temperature range of 1273 to 1473 K and strain rates of 0.01 to 30 s À1 were carried out. The influence of hot forging conditions (i.e., temperature, strain rate, and strain) on the microstructure of deformed sample was investigated in detail by means of electron backscattering diffraction (EBSD) and optical microscopy (OM). The results revealed that the initial microstructure is a stable face-centered cubic (FCC) phase with a large number of M 23 C 6 precipitates both inside the grains and at grain boundaries. The DRXed grains were observed to be uniformly distributed and to decrease with strain. The high volume fraction of AE3 boundaries after the DRX was observed, indicating a close relation between the DRX mechanism and AE3 boundary formations. In addition, the activation energy Q of CCMCN alloy was observed to be higher as compared to those of alloys without C or N addition and that with N addition.

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.…”

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

“…10) In this study, a detailed analysis in the relationship between hot-deformation behavior and microstructural evolution has been carried out by using processing map. In addition, new friction and adiabatic correction method was used to obtain the intrinsic stress-strain curves of materials in order to plot processing map with high precision.…”