Effects of casting temperature on some properties of Co-Cr-Mo dental casting alloys

Abstract

The castability of three Co-Cr-Mo-C alloys, taken as the percentage of a grid pattern that was filled by metal, increased almost linearly from less than 10% to nearly 100% when the casting temperature was increased by 150°C. The surface finish became poor only at the highest applied casting temperature (1635°C). The ductility was significantly reduced by increasing the volume fraction of eutectic hard particles containing carbides. These particles cracked in a direction vertical to the stress in tensile tests, initiating a brittle failure. They also affected the work-hardening rate, and their volume fraction increased with the content of C and Cr.

Key Words:

• Brittle fracture
• Carbides
• Castability
• Surface finish