Experimental determination of fully-coupled kinematical and thermal fields at the scale of grains under cyclic loading

A study was conducted to develop a method enabling an access to a fully-coupled measurement of kinematic and thermal fields of the same zone at the grain scale. The full-field measurements methods included infrared thermography (IRT) for temperature fields measurements and digital image correlation (DIC) for strain fields measurements. Necessary constraints and precautions were specified to reach a fully-coupled recording. Kinematic and thermal results obtained during a cyclic loading performed on AISI 316L stainless steel were presented and discussed. A Cedip Jade III infrared camera was used to perform thermal measurements. A precise calibration needed to be performed, the emissivity of the object had to be determined, and some precautions needed to be taken to perform accurate quantitative IRT. A calibration law was established by exposing the detector array of the camera in front of an extended blackbody at different controlled temperatures, creating a link bertween temperatures and thermal emissions.