Texture and shape memory strain in TiNi alloy sheets

Planar anisotropy of shape memory strain in polycrystalline TiNi alloy sheers was investigated in conjunction with crystallographic textures. To find the correlation between them, we attempted to predict shape-recoverable tensile strain from a measured texture by estimating volume fractions of correspondence-variants for each oriented grain. The recoverable strains calculated as a function of the angle to the rolling direction from a crystallite orientation distribution function were in relatively good agreement with experimental values for samples with different textures. A few samples, however, showed the quantitative differences between the measured and calculated values. The main reasons were clarified in view of yield stress and deformation constraint at grain boundaries. From an aspect of practical use. a manner of texture control to obtain higher recoverable strains has been discussed on the basis of the calculated results concerning representative ideal orientations. Copyright (C) 1996 Acta Metallurgica Inc.