## Materials Science and Engineering: An Introduction

$τ_{crss} = 0.91 MPa$
Given: single crystal of zinc is oriented for a tensile test such that its slip plane normal makes an angle of 65° with the tensile axis. Three possible slip directions make angles of 30°, 48°, and 78° with the same tensile axis Required: If plastic deformation begins at a tensile stress of 2.5 MPa (355 psi), determine the critical resolved shear stress for zinc Solution: Using Equation 7.4: $τ_{crss} = σ_{y} (cos φ cos λ)_{max} = (2.5 MPa)[ cos (65° ) cos(30° )] = 0.91 MPa$