Correction of intensities for preferred orientation in neutron-diffraction data of NiTi shape-memory alloy using the generalized spherical-harmonic description

Analysis of quantitative texture (crystallographic preferred orientation, PO) in polycrystalline materials is of interest not only because the PO gives errors in quantitative phase analysis, but also because it can affect the results of structure determination from powder diffraction data. In the present study, texture characterization of the polycrystalline Ni-rich NiTi shape-memory alloy (SMA) of nominal composition 50.14 atomic percent nickel has been carried out using the BT-1 high-resolution, fixed-wavelength, 32-detector powder diffractometer at the NIST Center for Neutron Research. Data were collected along the differential scanning calorimeter (DSC) heating curve. The results obtained from Rietveld refinement with the generalized spherical harmonic (GSH) description for all neutron diffraction data sets show that the weight percentages for monoclinic and cubic phases during the phase transition are consistent with the DSC heating curve.