Recovery of Elastic Properties and Internal Friction of Hydrostatically Extruded Molybdenum

Abstract : The recovery of the elastic properties and internal friction in various kinds of polycrystalline. Mo, deformed by extrusion to a degree of 0-80%, was studied with respect to the temperature of gradual isochronal annealing. The recovery of internal friction was complete in the 1st stage at 800-900C, which is below the temperature of the onset of recrystallization. The difference in the degree of deformation affected only the recovery rate and the temperature at which the change in internal friction became evident. Plastic properties recovered in 2 stages; at temperature up to 800-900C a approximately 50% recovery occurred owing to the fixation of dislocations by point defects. Total recovery of elastic properties was achieved in the 2nd stage as a result of complete recrystallization. The elastic properties of recrystallized Mo of various compositions are practically independent of a 10-fold growth of average grain size. (Author)