ABSTRACT
In LiH crystal both the critical resolved shear stress and the flow stress change with the change of strain rate became independent on the temperature below 5.2 K. In KCl crystal, however, such behaviors were not observed even though it was cooled down to 2.0 K. These results suggested that the dislocation tunneling was observed in LiH with light molecular-weight but not in KCl. The discrepancy of Arrhenius rate equation was found in both crystals in which the temperature range this discrepancy occuring was higher than that tunneling observed.
