Creep Tests on Axisymmetric Notched Bars: Global Displacement Measurements and Metallographic Determination of Local Strain and Damage

Abstract

Creep testing of notched bars has been shown to be an attractive technique for engineering purposes because it gives results on material creep resistance together with the possibility of checking the validity of mechanical computation methods on much simpler structures than actual components (Loveday and Dyson, 1979). In order to compare test data and computation results, specimens must be implemented with extensometers measuring global displacements. This first step of comparison, based on global response to loading, may be completed by local investigations, for a more confident validation of computed values of strains or damage: quantitative metallography is an interesting method for this second step of comparison. In this communication, mechanical test results and metallographical observations of grain shape and intergranular creep cracking damage are presented and compared to computed results, in the case of axisymmetric notched bars of a high creep resistant 17Cr-12Ni austenitic stainless steel.