Oxygen Desorption from Grain Boundaries of Molybdenum by Vacuum Heating

Abstract

The desorption behavior of oxygen from grain boundaries of polycrystalline molybdenum was studied and the deoxidation induced ductility recovery was examined. The desorption rate was controlled by the diffusion through grain boundary, and the diffusivity was given by AES analysis as D(m²⁄s)=7.8×10⁻³exp{−(270kJ/mol)⁄RT} in the temperature range from 1423 to 1743 K. A good correlation between the desorption behavior of oxygen and the elongation change in molybdenum was observed. The oxygen diffusivity derived from the measurement of the ductility change very closely agreed with that obtained by the oxygen analysis.