Development of new stress measurement method using neutron diffraction

Suzuki, Hiroshi  ; Minakawa, Nobuaki*; Moriai, Atsushi; Hataya, Mitsuhiko*; Morii, Yukio

In the conventional stress measurement method using neutron diffraction, it is required to measure the lattice strains of the same diffraction family in all three orthogonal directions. However, it is possibly difficult to measure the lattice strains of the same diffraction family in all three directions on the textured material, and also the lattice strains in three directions may not be measured in some reasons such as the size and the shape of the sample, etc. Moreover, in conventional method, it is required to know the accurate stress free lattice spacing d, so that the stress measurement accuracy depends on the accuracy of d of powder or annealed samples. In this study, we proposed new stress measurement method which can determine the residual stress states by measuring the lattice strains in two or three orthogonal directions even if the measured diffraction families were different in all three directions. Furthermore, stress measurement method which can determine the internal residual stresses without using measured d was also proposed.