Application of fractography to the study of carbon diffusion in molybdenum

Commercial pure molybdenum was immersed in a graphite-filled container and heated in vacuum at temperatures between 1073 and 1573K for 1.2ks. The fracture surface of the carbon-added specimen was examined using a scanning electron microscope (SEM). From the change of fracture mode as a function of distance from the specimen surface, the carbon diffusion distance was estimated. From Arrhenius plots of the carbon diffusion distance and the diffusion temperature we derived a diffusion parameter, like the activation energy for carbon diffusion in molybdenum of 182kJ. This value well agrees with the data that had been previously obtained using chemical composition analysis and/or activation analysis.