The factor k is the slope of straight line that is obtained when 0 is plotted against 0 . Many physical interpretations have been ascribed to the term. Which is roughly independent of temperature. The tern 0 is the intercept along the ordinate in a plot of 0 vs 0 . It is interpreted as the friction stress needed to move unlocked dislocations along the slip plane. This term depends strongly on temperature, strain , and alloy (impurity) content.