A study was made to determine the effect of alloying recrystallized molybdenum with nickel on the amplitude characteristic of internal friction and on microdeformation. Industrial grades MCh and MS of molybdenum were examined. Microdeformation, which is responsible for the amplitude dependence of internal friction in these grades of molybdenum within the 100-500‡K temperature range, has been found to be a thermally activated process and to be associated with the formation of double kinks. The activation energy, calculated from the temperature characteristic of the slope ∂δ/ ∂γ, is equal to (0.060±0.005) eV and does not change with alloying. It appears from the results of this study that the plasticizing action of nickel in recrystallized molybdenum is not related to the higher mobility of dislocations within the grain volume but, instead, is caused by the changing state of grain boundaries and manifests itself, only under conditions where strain is transmitted from grain to grain, in lowering the proportional limit Τ1 and extending the second stage of the microdeformation process (γpl,II).
ASJC Scopus subject areas
- Physics and Astronomy(all)