Characterization of thermal aging effects on the creep performance of T91 using small punch creep testing.

This paper is concerned with the development and application of a small punch creep testing method for assessment of the effects of thermal aging and associated precipitate coarsening on the high temperature creep life and deformation behavior of a 9Cr ferritic–martensitic steel. The tests are conducted on P91 steel, for both aged (up to 1 year) and unaged specimens, at temperatures of 600°C. The unaged test results are shown to be consistent with previously published creep tensile test rupture life data in terms of Chakrabarty membrane stress. Aging is shown to have a significant, detrimental effect on creep life and deformation rate. The steady‐state displacement rate, time to failure, and displacement at failure data, for both aged and unaged, were successfully correlated via the modified Monkman–Grant relationship. [ABSTRACT FROM AUTHOR]