MSE 230 HW4 (due 02/4, 02/5) Spring 2010 1. A cylindrical tensile test specimen is cut from a magnesium crystal such that the specimen axis, slip plane normal, and slip direction are coplanar ( λ + φ = 90°) and λ = = 45°. (a) If the critical resolved shear stress for slip on this slip system is 0.78 MPa, calculate the axial tensile (normal) stress at which slip would begin. (b) Make a sketch analogous to Fig. 7.7 (bottom half) showing the arrangement of atoms on the slip plane and in the slip direction. Draw the other two possible slip directions in the slip plane and explain briefly why they would not be preferred. 2. Tensile stress is applied along  in an aluminum alloy single crystal. If slip on (111) initiates at σ  = 6.8 MPa, calculate the critical resolved shear stress for this slip system. 3. A certain specification requires a metal alloy to have a yield strength of at least 310 MPa and ductility of at least 25% elongation. If cold-working is allowed, which of the three alloys for
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This note was uploaded on 11/11/2010 for the course MSE 230 taught by Professor Trice during the Spring '08 term at Purdue.