Influence of Microstructure on Synchrotron X-ray Diffraction Lattice Strain Measurement Uncertainty

Accurate residual lattice strain measurements are highly dependent upon the precision of diffraction peak location and underlying microstructure suitability. The suitability is related to requirement for valid powder sampling statistics associated number appropriately orientated illuminated. In this work, these two sources uncertainty separated, a method given both quantification errors with insufficient grain minimization total measurement uncertainty. It possible reduce by leveraging made at multiple azimuthal angles. Lattice data acquired during eight synchrotron X-ray experiments, monochromatic energy dispersive, has been assessed as per approach, microstructural being seen dominate when illuminated grains was <106. More than half studied experimental fell into category, severe underestimation not considered. To achieve under 10−4, approximately 3×105 must be within sampled gauge volume, value varying multiplicity family planes study. Where additional azimuthally arrayed available an in-plane tensor can extracted. This improves overall accuracy 10−4 then achieved just 4×104 grains.