Effect of heat-treatment on the texture and anisotropy of transformation strain in Ti–Ni–Fe rolled thin plates

Abstract

Rolling and annealing processes were applied to make Ti–50.5Ni–0.4Fe (at.%) thin plates. Such processes create a specific texture in the plates, and the texture causes an anisotropy of transformation strain to appear. The purpose of this study is to investigate the effect of annealing on the texture and anisotropy of the transformation strain in Ti–50.5Ni–0.4Fe (at.%) plates with a cold-rolling reduction of 37.5% and a thickness of 100 μm. They were annealed at 673, 873 and 1273 K, respectively, for 3.6 ks. A crystallite orientation distribution function (ODF) was measured by using diffraction from {110}, {211} and {200} planes. Inverse pole figures were drawn on the basis of the ODF. Using the crystallite axis density in the inverse pole figures, the transformation strain was calculated as a function of the angle from the rolling direction (RD) in the rolling plane. In the rolling plane, the transformation strain was almost constant in a range of the angles from 0 to 30°, and decreased with a further increase of the angle. The anisotropy of the transformation strain in the rolling plane became strongest in a specimen annealed at 873 K.