Avoiding or Promoting Graphite in Carbon-Rich Chromium-Containing CoNiFe Cast Alloys—Part 1: Preliminary Thermodynamic Exploration

The thermodynamic equilibria of alloys, based on Co, Ni, and Fe rich in chromium and carbon over a [500; 1500°C] range of temperature, were determined using thermodynamic calculations. The probable types of microstructures (hypo- to hypereutectic) as well as the phase present at high temperature (matrix network, types of carbides, presence or not of graphite) were predicted. From these results new chromium contents to either avoid or promote the presence of graphite were chosen and the as-cast microstructures of the corresponding real alloys were anticipated, before their elaboration and microstructure characterization in the second part of this work.