DAMAGE ACCUMULATION AND MICROSTRUCTURAL CHANGES OCCURRING DURING THE CREEP OF A 2 1/4-PERCENT-CR1-PERCENT-MO STEEL

Uniaxial creep tests were carried out on a 2 1 4%Cr1%Mo steel with a prior austenite grain size of 80 μm under constant load conditions with initial stresses in the range 55 - 76 MPa and temperatures in the range 838 - 923 K. Scanning electron fractography was used to assess the rate of grain boundary damage accumulation. Transmission electron microscopy was used to characterize the microstructural changes resulting from the grain deformation. The results are discussed in terms of providing diagnostic information in order to predict residual creep life. © 1979.