Stress Measurement Technique using Neutron Diffraction and its Applications

Abstract

  Neutron diffraction is the only method by which residual stresses inside materials at centimeter-order depth can be measured nondestructively. Residual lattice strains in (hkl) can be evaluated from the shift of the diffraction peak from its original position under the stress-free condition. Residual stresses can be calculated by applying Hooke's law to lattice strains measured in three orthogonal directions. In addition, the neutron diffraction method can evaluate macroscopic deformation of engineering materials by measuring microstructural factors such as microstrains. Therefore, the neutron diffraction technique is very helpful in the design and development of engineering components, as well as in studies on materials engineering. This paper shows principle of neutron stress measurement and engineering neutron diffractometers as well as some applications.