Study on the interaction between a dislocation and impurities Part X Relation between the strain-rate sensitivity and the stress decrement due to superposition of oscillatory stress for KCl single crystals doped with monovalent impurities

Strain-rate cycling tests during the ultrasonic oscillation were carried out at 80－300 K for two kinds of single crystals: KCl:Li+ (LiCl 0.5 mol% in the melt) and KCl:Na+ (NaCl 0.5 mol% in the melt). Two bending points and two plateau places were observed on the strain-rate sensitivity versus stress decrement curve for both the specimens. The first bending point at low stress decrement, τp1 , shifted in the direction of low stress decrement with increasing temperature. τp1 decreased with temperature as the variation of the critical resolved shear stress within the temperature. The critical temperature, Tc , at which τp1 is zero could be estimated to be around 250 K for KCl:Li+ and 270 K for KCl:Na+.

plastic deformation

strain-rate cycling tests

ultrasonic oscillation

critical temperature