Sample tilt-free characterization of residual stress gradients in thin coatings using an in-plane arm-equipped laboratory X-ray diffractometer

A methodology is presented to characterize residual stress gradients using the sin²ψ technique at constant penetration depths without the use of sample χ tilting. The experiments were performed using a laboratory five-axis X-ray diffractometer equipped with an in-plane arm by scanning several reflections in order to enlarge the penetration depth range. The proposed approach, demonstrated on a blasted 11.5 µm-thick TiN coating on a WC–Co substrate, opens the possibility to perform a complex stress gradient characterization in laboratory conditions where the sample χ tilting can deteriorate the sample properties or experimental conditions, like during in situ high-temperature studies.