Peierls Stresses Estimated from CRSS vs. Temperature Curve and Their Relation to the Crystal Structure

摘要

Peierls stresses τ_P of a variety of pure crystals, bcc metals, NaCl type crystals, elemental and compound tetrahedrally coordinated crystals, intermetallic compounds and ceramic crystals, have been estimated from the critical resolved shear stress (τ_c) vs. temperature curves. For high τ_p crystals where CRSS data are available only at high temperatures, τ_p has been estimated from the critical temperature T_0 at which steep temperature dependence of τ_c vanishes: T_0 is related to the kink-pair formation energy which is a function of τ_P, material parameters and dislocation character controlling the deformation. The estimated τ_p/G values are semi-log plotted against h/b value, where G is the shear modulus, h the slip plane spacing and b the Burgers vector. Two facts should be noted. First, τ_p/G values for a group of crystals with the same crystal structure are within a range of a factor of 10. Second, most of the data points lie in between the classical Peierls-Nabarro relation and the Huntington's modified relation. These facts indicates that Peierls stress is primarily determined by the crystal structure.