Is it a solid or a powder sample? You can measure surface residual stresses in solids with XRD but not bulk stresses.
For solid sample, you can measure with XRD.
I agree with Dr. Jackson, only for surface residual stress.
Residual stress (RS) measurement by XRD using typical lab sources is generally only going to measure the top 5-25 microns, depending on the material and the x-ray energy. We routinely measure RS depth profiles by successive surface measurements followed by electropolishing. Electropolishing is like electroplating in reverse and can remove material without altering the stress state. We then make corrections to the successive surface measurements (made on the newly exposed surface, which was formerly a buried layer) for stress gradient and the influence of the stresses in the removed layers. (www.protoxrd.com)
Regarding whether you need a standard: This is a truely wonderful thing about the usual RS measurement method of plotting observed d-spacing versus sin2(psi). Where psi is the angle between the scattering vector and the sample normal. In the sin2(psi) plot, the slope is proportional to the stress. No need for accurate knowledge of unstressed d-spacing! Thus a series of very precise measurements (even if not individually accurate), can give a highly accurate result. That is very cool!
http://protoxrd.com/residual-stress-info.html
http://protoxrd.com/recommended-reading.html
Why would you measure residual stress on powder? Firstly, do you speak about macroscopic (or the 1st order) or microscopic (2nd order) or even submicroscopic (3rd order) residual stresses? For the macroscopic RS, you can fully characterize them by 2nd order symmetrical tensor, which is reasonable for example for ground, milled or in general anisotropically surface treated objects. But for powder, there could of course be some macroscopic residual stresses, but how will you find the reference coordinates? Nevertheless, you can load your powder into a proper sample holder (preferably by a side loading technique) and try to measure a suitably chosen high angle profile under several tilts. I would expect equi-biaxial stress state if any (for biaxial stress state you don't really need to know the d0 stress-free value)....In powders, you probably usually want to determine microstresses and that is usually done by profile analysis and using Rietveld refinement....
To measure just the surface tension it is possible to use the technique of test inks. We draw a line of ink on the material and according to the reaction of the ink one chooses the ink of a level higher or lower, and so on until we find the surface tension level of the material. Maybe correlation exists in the literature which correlates for shallow thickness the surface tension and the residual stresses.
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