Method to determine hkl strains and shear moduli under torsion using neutron diffraction

An experimental method, using in-situ neutron diffraction for the measurement of shear strain, based on (hkl) lattice spacing changes under torsional loading, is described. This method provides the ability to probe the response of crystallographic planes to application of shear stress, inside the bulk of samples that are subjected to torsion. To demonstrate the method, shear moduli corresponding to bcc (211), (200), and (110) were experimentally determined for a solid cylinder of ferritic alloy 12L14 under elastic loading. Results indicate that the elastic constants determined under torsional shear show a different degree of anisotropy than those obtained from tensile loading. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4712043]