No abstract

The precipitation behavior of carbides in Fe-5.78Cr-0.35C (wt.%) alloy during aging at 850°C was studied. The type, particle size and distribution of carbides were determined and measured by the combination of HRTEM (High Resolution Transmission Electron Microscope), XRD (X-Ray Diffraction) and quantitative metallography technique. Results show that the type of carbides was M7C3 and the obvious coarsening of carbides was observed during aging. In addition, the thermodynamic and kinetic calculation using Thermo-Calc software was conducted to study the precipitation of carbides. The stable phase in the alloy aging at 850°C was M7C3 carbide and austenite which is in accordance with experimental results. According to Ostwald coarsening mechanism, the average interfacial energy between γ phase and M7C3 carbide was calculated as 0.7 J·m-2. Then the precipitation behavior of carbides in Fe-5.78Cr-0.35C alloy during aging was well predicted.