Phase identification and incipient melting in a cast Co‐Cr surgical implant alloy

Abstract

Phase relationships in cast Co--Cr surgical implant alloys, heat treated at temperatures from 1180 to 1300 degrees C, are reported. Interdendritic material was identified by selected area diffraction as a quaternary near eutectic mixture between sigma phase, M23C6, M7C3, and fcc Co. Incipient melting and subsequent resolidification of this near-eutectic mixture accounts for observations of behavior at temperatures above 1235 degrees C. At temperatures just below its melting point the interdendritic material initially breaks down to M23C6, which subsequently dissolves in the Co matrix.

Friction-Wear Properties of Nickel-Free Co–Cr–Mo Alloy in a Simulated Body Fluid

“…Co-Cr-Mo cast alloys consist of coarse grains and contain phase concentrating Co, M 23 C 6 phase containing Co and Mo, carbides of Co, Cr and Mo, and dendrite structure concentrating Cr and Mo. 1,2) On the other hand, Co-Cr-Mo wrought alloys consist of fine and uniform grains and show better tensile strength, yield strength and elongation than cast alloys and heat-treated alloy. 2,3) The wrought alloys also contain fine carbide structures.…”

Up-to-Date Knowledge and Outlooks for the Use of Metallic Biomaterials: Review Paper

“…However, according to some research, e.g., [6], stainless steels can sufer piting, crevice, corrosion fatigue, stress corrosion cracking, and galvanic corrosion within the human body accelerated by their reduced wear resistance. Additionally, appearance of allergic reaction limits their use as orthopedic joint prosthesis [7,8].…”

Friction-Wear Properties of Nitrogen-Ion-Implanted Nickel-Free Co–Cr–Mo Alloy

“…Co-Cr-Mocast alloys consist of coarse grains and contain a phase of Co, a M 23 C 6 phase containing Co and Mo, carbides of Co, Cr, and Mo, and a dendrite structure of Cr and Mo. 1,2) On the other hand, Co-Cr-Mo wrought alloys consist of fine and uniform grains and show better tensile strength, yield strength, and elongation than cast alloys and heat-treated alloys. 2,3) The wrought alloys also contain fine carbide structures.…”