Standard Practice for Verifying the Alignment of X-Ray Diffraction Instruments for Residual Stress Measurement

Importancia y uso:

4.1 This practice provides a means of verifying the alignment of an X-ray diffraction instrument so as to quantify and minimize systematic experimental error in residual stress measurements. This practice is suitable for application to conventional X-ray diffraction instruments or to X-ray diffraction residual stress measurement instruments of either the diverging or parallel beam types3^,4

4.2 Application of this practice requires the use of a flat stress-free specimen that diffracts X-rays within the angular range of the diffraction peak to be used for subsequent residual stress measurements. The specimen shall have sufficiently small coherent domains or grains, be quasi-homogeneous, quasi-isotropic, and be of sufficient thickness such that incident X-rays interact with and diffract from an adequate number of individual coherent domains or grains such that a near-random grain orientation distribution is sampled. The crystals shall provide intense diffraction at all tilt angles ψ that will be employed.

Note 1: A major bias in crystal structure orientation is undesirable, but complete freedom from preferred orientation in the stress-free specimen is not critical in the application of the technique.

Subcomité:

E28.13

Referida por:

E2860-20

Volúmen:

03.01

Número ICS:

19.100 (Non-destructive testing)

Palabras clave:

alignment; residual stress; stress-free specimen; systematic error; x-ray diffraction ;