Ternary Phase Equilibria in Transition Metal-Boron-Carbon-Silicon Systems. Part I. Related Binary Systems. Volume XI. Final Report on the Mo-C System

摘要

The binary alloy system molybdenum-carbon was investigated by means of X-ray, metallographic, thermoanalytical, and melting point techniques on chemically analyzed specimens. The system is characterized by three congruently melting, intermediate phases, Mo2C, ETA-MoC(1-X), and Alpha-MoC(1-X), of which only Mo2C is stable at temperatures below 1650C. Substoichiometric (is greater than 32.5 at % C) dimolybdenum carbide undergoes a homogeneous sublattice order-disorder transformation at temperatures of approximately 1400C, whereas hyperstoichiometric compositions undergo a discontinuous phase-change. The order-disorder transitions in the Me2C phases are discussed in terms of the structural changes involved in the transformation processes. (Author)