ε = ce{3. Assume the activation energy for the creep of Al2O3 is 425kJ/mol. (a) Predict thecreep rate, &, for Al2O3 at 1000°C and 1800 psi applied stress. (See Table 6.12 fordata at 1300°C and 1800psi.) (b) Calculate the lifetime of an furnace tube at 1000°Cand 1800 psi if 1% total strain is permissible.(ε = 2.7x10-6/hr for Al2O3 at 1300°C and 1800psi.) TABLE 6.12Creep-Rate Data for Various Polycrystalline CeramicsMaterialAl2O3BeOMgO (slip cast)MgO (hydrostatic pressed)MgAl2O4 (2-5 μm)MgAl2O4 (1-3 mm)ThO2ZrO2 (stabilized)è at 1,300°C, 1,800 psi (12.4 MPa)[mm/(mm. h) x 106]1.3300.0330.033.0263.01.01,000.030.0Source: W. D. Kingery, H. K. Bowen, and D. R. Uhlmann, Introduction toCeramics, 2nd ed., John Wiley & Sons, Inc., New York, 1976.

To find: The creep rate and the lifetime of an furnace tube. Given: Activation energy, Q = 425…

3. Assume the activation energy for the creep of Al2O3 is 425kJ/mol. (a) Predict the creep rate, &, for Al2O3 at 1000°C and 1800 psi applied stress. (See Table 6.12 for data at 1300°C and 1800psi.) (b) Calculate the lifetime of an furnace tube at 1000°C and 1800 psi if 1% total strain is permissible. ( = 2.7x10-6/hr for Al2O3 at 1300°C and 1800psi.)

3. Assume the activation energy for the creep of Al2O3 is 425kJ/mol. (a) Predict the creep rate, &, for Al2O3 at 1000°C and 1800 psi applied stress. (See Table 6.12 for data at 1300°C and 1800psi.) (b) Calculate the lifetime of an furnace tube at 1000°C and 1800 psi if 1% total strain is permissible. ( = 2.7x10-6/hr for Al2O3 at 1300°C and 1800psi.)

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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