MSE2160 Problem Set 5 Chapters 8 and 9: Deformation and Failure, due electronically via Canvas on Wednesday, March 20th 1. (a) Show, for a tensile test, that %CW = 1+€ € * 100 if there is no change in specimen volume during the deformation process (i.e., Aolo = Adla). (b) Using the result of part a, compute the percent cold work experienced by naval brass (the stress-strain behavior of which is shown below) when a stress of 400 MPa is applied. 500 70 Tensile strength 450 MPa (65,000 psi) 60 400 A 103 psi 50 Stress (MPa) 300 MPa 40 Stress (103 psi) 40 30 200 Yield strength 30 200 20 250 MPa (36,000 psi) 100 20 10 1 100 1 10 1 0 0.005 0 0 0 0.10 0.20 0.30 0.40 Strain 2. The average grain diameter for a brass material was measured as a function of time at 650 ℃ and data was collected. After 30 minutes, the grain size was 3.9x10-2 mm and after 90 minutes the grain size was 6.6x10-2 mm. a. What was the initial grain size? b. What is the grain size after 150 minutes? c. If the initial yield strength is 160 MPa and the coefficient ky is 12 MPa-mm1/2, what are the yield strengths after 30, 90, and 150 minutes? d. If we wait a very long time at 650 ℃, what will be the yield strength of this brass material?