The phenomenon that the effective stress (τp1) due to the impurities decreases with increasing shear strain was observed at almost all the temperatures for KCl:Na+ (NaCl 0.5 mol% in the melt). On the other hand, it could not be discerned for KCl:Li+ (LiCl 0.5 mol% in the melt). Accordingly, the critical temperature, at which the effective stress is zero, is larger in stage Ⅰ of stress-strain curve, compared with that in stage Ⅱ. Furthermore, the value of τp0 , the effective stress due to the impurities without thermal activation, in stage Ⅰ is slightly larger than that in stage Ⅱ for KCl:Na+.
effective stress due to impurities
critical temperature
plastic deformation