High-temperature tensile property measurements using digital image correlation over a non-uniform temperature field

摘要

Standard test methods for measuring temperature-specific mechanical properties are typically specimen and time intensive when the influence of varying parameters is taken into consideration. Often, multiple specimens and test runs are required to build a complete database of constitutive parameters. This article presents a numerical-experimental methodology that employs digital image correlation to measure temperature-specific tensile properties of a 12% Cr steel. The methodology presents the unique ability to obtain temperature-specific properties from a single sample: the sample is subjected to a longitudinal thermal gradient through resistive heating in a thermomechanical loading system, while the full-field capabilities of digital image correlation and thermal imaging are used to measure strain and temperature surface maps, respectively. A study on the robustness of the methodology with regard to image saturation control and stress state found the setup capable of deformation measurement up to 900 degrees C. Elastic moduli and Poisson's ratios were extracted in the 480 degrees C-600 degrees C range from a single specimen. The presented metrology sets the framework for investigations that are aimed at extracting temperature-specific mechanical properties for 12% Cr steels.