Stress measurement of an austenitic stainless steel foil by transmitted polychromatic X-rays

Deformation properties of austenitic stainless steel foils of 0.05 mm in thickness were evaluated by using transmitted polychromatic X-rays under monotonic tensile loading. A conventional laboratory X-ray equipment with a rotating Mo anode was adopted at a tube current of 40 mA and an acceleration voltage of 60kV. Soller slits with a divergence angle of 0.5 deg were attached on both divergent and receiving sides. By the preset time of 500s, enough diffraction intensity was obtained to determine the stress. The diffraction elastic constants were measured under monotonic loading by the cos 2χ method. The diffraction energy decreased almost linearly with increasing cos2χ , and the slope of the cos2χ diagram decreased with increasing applied stress. Measured diffraction elastic constants were compared with the theoretical values calculated by the Kröner model. The experimental value obtained from a single peak with high intensity agreed well with theoretical one, and the standard deviation was enough small. The lattice strain measured during plastic deformation depended on the diffraction plane. For the single peak profile, the full width at half maximum increased with applied plastic strain. From the the diffraction-plane dependence of the lattice strain, the full width at half maximum and the diffraction intensity, deformation properties of the materials can be evaluated. Diffraction method of laboratory polychromatic X-rays is effective as a simple technique to measure multiple X-ray parameters. © 2011 The Society of Materials Science, Japan.