Neutron Diffraction Method

Multi-component bulk residual stress mapping

Neutron Diffraction is a specialized measurement technique used to develop bulk residual stress data in thick sections. The method can be applied to quantify the average residual stress over the measurement gage volume (8 to 125 mm3 is the typical gage volume). Rotating the specimen in different orientations allows for the measurement of multiple residual stress components and translating the specimen allows for the measurement of multiple points within the body. Many points within the body can be measured in multiple orientations to generate a 2D (or 3D) residual stress map.

Neutron Diffraction residual stress measurements require a neutron source, which is only available at specialized facilities (e.g., national laboratories). Hill Engineering works with beamline staff to plan and execute neutron diffraction measurements.

Neutron diffraction is useful for

  • Measuring multiple stress components in three dimensions
  • Mapping residual stresses in large sections
  • Parts with large or complex geometry

Photograph of a neutron diffraction residual measurement on an aluminum alloy T-section at the High-Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL)

Line plot of residual stress versus position from the center of a linear friction weld on a Ti-6Al-4V test specimen measured using neutron diffraction and the contour method.