Experimentally, it has been observed for single crystals of a number of metals that the cr...

Experimentally, it has been observed for single crystals of a number of metals that the critical resolved shear stress τcrss is a function of the dislocation density ρD as

where τ0 and A are constants. For copper, the critical resolved shear stress is 2.10 MPa (305 psi) at a dislocation density of 105 mm–2. If it is known that the value of A for copper is 6.35 × 10–3 MPa mm (0.92 psi mm), compute τcrss at a dislocation density of 107 mm–2.