Ternary Phase Equilibria in Transition Metal-Boron-Carbon-Silicon Systems. Part II. Ternary Systems. Volume IV. The Ti-Zr-C, Ti-HF-C and Zr-HF-C Systems

摘要

Solid-state sections of the ternary Ti-Zr-C and Ti-Hf-C systems were investigated; the complete Zr-Hf-C system was studied from 1600 C to melting using X-ray, DTA, melting point, and metallographic techniques on chemically analyzed alloys; a complete phase diagram for the Zr-Hf-C system for temperatures above 1600 C was established. The Ti-Zr-C system contains a miscibility gap in the monocarbide region; the miscibility gap is completely closed at temperatures above approximately 2150 C. A miscibility gap is also present in the Ti-Hf-C system in the monocarbide region; complete solid solubility exists between the binary monocarbides at temperatures above approximately 2050 C. The Zr-Hf-C system contains a high melting, continuous monocarbide solidsolution in a carbon defect lattice. The Alpha-hafnium phase is stabilized toward higher temperatures by carbon; this phase shows a moderate solubility for carbon and zirconium. (Author)