Effect of Thermomechanical Processing on Texture and Superelasticity in Fe–Ni-Co-Al–Ti-B Alloy

Abstract

The texture and superelasticity were investigated in austenitic Fe–Ni-Co-Al–Ti-B alloy with various reduction ratios of cold rolling and heating ratios in annealing. The rolled sheets show the {110} 〈112〉 deformation texture at a reduction ratio higher than 80%, while the texture hardly changes in the primary recrystallization at 1000 °C. The β (B2) precipitates inhibit the grain growth at this temperature, but they dissolve during heating, and secondary recrystallization occurs due to decreased pinning force at temperatures higher than 1100 °C, resulting in texture change to {210} 〈001〉 . The recrystallization texture is more strongly developed when the reduction ratio and heating rate are high and slow, respectively. The 90% cold-rolled and slowly heated sheet shows the recrystallization texture and high fraction of low-angle boundaries. As a result, ductility and superelasticity can be drastically improved in the 90% cold-rolled sheet, although superelasticity was previously obtained only in thin sheets with 98.5% reduction.