Harper-Dorn creep in single crystalline NaCl

Abstract

I-Iaxper-Dorn (H-D) creep is a Newtonian-viscous observed in crystalline solids at low sue.ues and intermediate-to-high temperatures. Harper-Dorn creep is generally characterized by [1-5]: (i) a ratecontrolling mechanism involving dislocation motion, (ii) creep rates that are often independent of grain size,.(iii) creep rates that .me faster than those inedicted by the .dit.Yus. lonal creep mechanisms [6-8], and (iv) a stress independent dislocatmn density. Recently, a model to explmn Harper-Dorn creep based on the presence of an internal stress, arising from random dislocations within subgrains, has been successfully used to predict the Harper-D¢~ creep behavior in twelve pure metals [9,10], five metallic solid solution alloys [I 1,12], and a ceramic oxide, uranium dioxide [13].