Wimpory, R.C.; Hofmann, M.: Use of Symmetry for Residual Stress Determination. In: Seefeldt, Marc [Ed.] : European Conference on Residual Stresses 2018 : ECRS-10 . MRS, 2018 (Materials Research Proceedings, 6). - ISBN 978-1-945291-89-0, p. 9-14
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Instrumental and certain sample characteristics can affect the detected Bragg peak shifts which are not related to the strain being measured. Three major effects can influence the measurement: the surface effect, where the instrumental gauge volume (IGV) is not fully immersed at a surface or interface, the grain size effect where there is random positioning of large grains in the sample within the gauge volume and the relative shift in position of the centre of gravity of measurement due to absorption of neutrons. All of these effects can be reduced/eliminated by making pairs of neutron diffraction measurements 180 degrees to each other at the same location. Results are presented from a round robin benchmark weldment, denoted TG6, from the European Network on Neutron Techniques Standardization for Structural Integrity (NeT). This is made from a nickel alloy which has large grains and strains and has a high neutron attenuation coefficient.