Quasiviscous mass transfer in the high-temperature creep of polycrystals

For the example of lead-based alloys, the nature of the grain-surface distortion and its contribution to the deformation in the high-temperature creep of polycrystals is investigated. It is shown that quasiviscous flow associated with nondiffusional motion of atoms in conditions of a strongly excited state of the crystal makes a definite contribution to the distortion of the initially plane grain surface. The development of this deformation mechanism is facilitated by a high test temperature, motion of the grain as a whole in the deforming polycrystal, and the presence of boundary-seeking impurities with strongly different atomic volumes in the alloy in comparison with the base metal.