(a) Estimate the activation energy for creep (i.e., Qc in Equation 9.21) for the S-590 all...

(a) Estimate the activation energy for creep (i.e., Qc in Equation 9.21) for the S-590 alloy having the steady-state creep behavior shown in Figure 9.38. Use data taken at a stress level of 300 MPa (43,500 psi) and temperatures of 650°C and 730°C. Assume that the stress exponent n is independent of temperature.

(b) Estimate at 600°C (873 K) and 300 MPa.

Figure 9.38 Stress (logarithmic scale) versus steady-state creep rate (logarithmic scale) for an S-590 alloy at four temperatures.

 (9.21)