(Solved): 7. () (a) From the plot of yield strength versus (grain diameter) 1/2 for a 70 Cu - 30 Zn ...

7. (???) (a) From the plot of yield strength versus (grain diameter) 1/2 for a 70 Cu - 30 Zn cartridge brass in Figure 7.15, determine values for the constants of and ky in ?? = ?o + k?d-¹/2 Equation 7.7. (b) Now predict the yield strength of this alloy when the average grain diameter is2.0 Grain size, d (mm) 10-¹ 10-² 5x 10-3 30 200 Figure 7.15 The influence of grain size on the yield strength of a 70 Cu-30 Zn brass alloy. Note that the grain diameter increases from right to left and is not linear. (Adapted from H. Suzuki, "The Relation between the Structure and Mechanical Properties of 150 Metals," Vol. II, National Physical Laboratory, Symposium No. 15, 1963, p. 524.) Z 100 10 50 0 0 8 12 d-1/2 (mm-1/2) X10-³ mm. Yield strength (MPa) 8 Yield strength (ksi) 16 4