Orowan showed that the shear strain rate is given by γ? = dγ /dt = ρbv, where ρ is the dislocation density and v is the average velocity of the dislocation. In a tension test, the tensile strain rate, ε?, is half of the shear strain rate, γ? (ε? = (1/2)γ?. If the Schmid factor = 1/2; otherwise ε? (1/2)γ? . In a typical tension test, the crosshead rate is 0.2 in./min and the gauge section is 2 in. in length. Estimate v in a typical tension test for a typical metal with an initial dislocation density of 1010/cm2.