ASM Co-139 PDF

Deloro Stellite 21 (UNS R30021), previously known as Stellite 8, is similar to the medical implant alloy ASTM F75. It is a Co-Cr-Mo-Ni alloy that was developed in the mid-1930s as a corrosion resistant alloy, and rapidly found application as a biocompatible hip implant and denture alloy. This alloy consists of a CoCrMo alloy matrix containing dispersed hard carbides that strengthen the alloy and increase its hardness, but that also decrease its ductility. The type, shape, size, and distribution of the carbides are strongly influenced by the processing history of the alloy, and for this reason, the mechanical properties of Deloro Stellite 21 depend greatly on the manufacturing route and any subsequent heat treatments.