3. An uncold-worked brass specimen of average grain size 0.01 mm has a yield strength of 150MPa (21,750 psi). Estimate the yield strength of this alloy after it has been heated to 500°C for 1000 s, if it is known that the value of o, is 25 MPa. (Note that the axis has logarithmic scale).

Fig: 1

Fig: 2