Low Temperature Internal Friction and Modulus Change in Plastically Deformed Iron Single Crystals

Abstract
An experimental study is made of internal friction and modulus change of iron single crystals containing small amounts of interstitial impurities. Measurements are made over a temperature range from 5°K to 150°K, and a broad thermally activated relaxation peak of internal friction is observed near 50°K at the frequency of 100 kHz for the specimens deformed in tension at room temperature. This relaxation peak of Fe single crystals resembles that of other b.c.c. metals such as Nb, Mo, Ta and W. It seems likely that the elementary process which contributes to the thermally activated process at low temperatures is a motion of geometrical kinks produced by the room temperature deformation.