Initiation of dislocation multiplication in lithium fluoride monocrystals under impact loading

Abstract
An experimental impact technique is described for exposing materials to small amplitude stresses in states of uniaxial strain for small times. It is applied to single crystals of LiF containing ∼8 ppm Mg, and multiplication of screw dislocations is measured. For shear impulses exceeding about 40 dyn sec/cm2, multiplication is adequately described by multiple cross glide with multiplication coefficient m= (2–4) ×109 cm−2. For shear impulses less than 20 dyn sec/cm2, no multiplication is observed. Stress amplitude and duration are varied independently.