GB/T 26140-2010

This standard specifies the method for measuring residual stress in polycrystalline materials by neutron diffraction. This standard is applicable to uniform and non-uniform materials, as well as bulk samples containing different crystal phases.
This standard briefly introduces the principle of neutron diffraction technology, provides recommendations for the corresponding diffraction crystal planes when measuring different types of materials, and provides guidance on how to select the measurement direction and the volume to be measured related to the grain size and stress state of the tested materials.
This standard describes the process of accurately locating and correcting the detection site within the neutron beam, with the aim of being able to precisely define the sampling volume of the sample material during measurement.
This standard describes the issues that need to be paid attention to when calibrating neutron diffraction devices, and introduces the technical methods for obtaining stress-free reference values.
This standard details the methods for measuring various elastic strains by neutron diffraction, clarifies the process of analyzing the results and determining the statistical correlation, and provides recommendations on how to obtain reliable residual (or applied) stress from the strain data and how to evaluate the uncertainty of the results.