A turbine blade, made of the 12% Cr steel of Exercise E8.22, is 10 cm long and runs with an initial clearance of 100 μm between its tip and the housing in a generator operating at 515°C. Determine the lifetime of the blade (meaning the time before it fouls the housing) if it runs continuously, assuming a uniform tensile stress of 60 MPa is applied along its axis. (The creep activation energy Q for 12% Cr steel is 270 kJ/mol, n=6, ε_(0)˙=6 x 10^8/s, and σ_(0)=100 MPa).
