Clay, K*; Jackson, J D*; Quested, P N; Morrell, R (2009) Improving single-crystal orientation determination for advanced nickel-based alloys. Measurement Good Practice Guide. 112

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Abstract

This Good Practice Guide describes the determination of single-crystal orientation measurements for single-crystal nickel-base castings by back and side-reflection X-ray diffraction (Laue). These measurements check the quality of the castings against specifications set by the OEMs for the foundries.
For quality control three parameters are determined:
1. The angle between a reference direction in the component, defining the preferred direction of solidification, and the closest <100> direction. (q).
2. Less commonly, the angle between a second reference direction in the plane perpendicular to the original reference direction (a) and/or a <001> direction (k).
3. For single crystals with more than one grain a measurement of the misorientation or disorientation between adjacent grains (R).
The guide contains information about the definition of orientation parameters; principles of back-reflection and side-reflection Laue systems; calibration standards; system alignment; calibration; validation and uncertainty of measurements with a final section on making the measurements.
The definition of primary angles is based upon European practice but a comparison with two definition conventions used in the USA is included.

Item Type:	Report/Guide (Measurement Good Practice Guide)
Notes:	NPL made every effort to ensure all information contained in this Good Practice Guide was correct at time of publication. NPL is not responsible for any errors, omissions or obsolescence, and does not accept any liability arising from the use of these Good Practice Guides.
Keywords:	Single crystals, X-rays, Laue patterns
Subjects:	Advanced Materials Advanced Materials > Microstructural Characterisation
Last Modified:	23 Feb 2026 09:01
URI:	https://eprintspublications.npl.co.uk/id/eprint/4548