Calibration of machine deformation for quasistatic fracture toughness testing at high temperatures

Abstract

Quasi-static J testing at elevated temperatures can be simplified to a great extent if extensometry for load line displacement measurement can be avoided. Towards this, a procedure has been developed for calibrating the non-linear elastic machine deformation as a function of load, using data for a blank specimen deforming in the elastic regime. The calibration procedure is demonstrated for ambient temperature 653 and 803 K. For a modified 9Cr–1Mo steel under the normalised and tempered condition without/with subsequent thermal aging, the viability of the calibration method for evaluating J is demonstrated for the two elevated temperatures.