Influence of Carbon Content in Cobalt-Based Superalloys on Mechanical and Wear Properties

Abstract

Two cobalt-based superalloys containing 1.6% and 2% carbon respectively were studied, with the emphasis on the influence of the carbon content on their microstructures, wear resistance, and mechanical properties. Phase formation and transformation in the microstructures were analyzed using metallographic, X-ray diffraction, and differential scanning calorimetry techniques. Wear resistance, tensile and fatigue behaviors of the alloys were investigated on a pin-on-disc tribometer, MTS machine and rotating-bending machine, respectively. It is found that the wear resistance was increased significantly with the carbon content. The mechanical properties of the alloys are also influenced by the carbon content, but the impact is not so significant as on the wear resistance. It was observed that the carbon content increased the yielding strength and fatigue strength, but decreased the fracture stress and fracture strain.