The System Zirconium—Carbon

Abstract

Phase relations in the system zirconium‐carbon were established by DTA, X‐ray, and metallo‐graphic methods. Only one phase, a monocar‐bide with the NaCl structure, was found. The low‐carbon phase boundary for the monocarbide contains 38.5 at.7, carbon between 1900’and 3300OC. The carbon‐rich boundary between 2850” and 330O°C is at 48.9 at.% carbon. ZrC melts congruently at 342O°C and 46 at.% carbon. The lattice parameter versus composition curve shows a maximum at 46 at.% carbon. The Zr‐ZrC eutectic is at 186O°C and 1 at.% carbon; the Zr‐ZrC eutectic is at 285O°C and 65 at.% carbon. Liquidus curves are inferred from the invariant points.