Measurement of strain free lattice spacing in neutron residual stress analysis by sample rotation method

In a high accuracy residual stress measurement by the neutron diffraction method, it is important to obtain the d0(hkl), the lattice spacing of strain free in the measurement material, exactly. We attempted new method to measure the d0(hkl) by neutron diffraction while sample is rotating at random as an easy method. In this study, the d0(hkl) of the extra super duralumin with texture was measured by our method. This technique is a method of calculating d0(hkl) from a0 obtained by the extrapolation method. To examine the reliability of this new method, the a0 obtained by new technique was compared with the a0 obtained by the conventional powder neutron diffraction. Their differences were 8 x 10-5 nm or less. This result confirms that a0 and d0(hkl) with enough accuracy are obtained by this new technique for the neutron residual stress analysis. (author)