An EBSD investigation of ultrafine-grain titanium for biomedical applications

High-resolution electron backscatter diffraction (EBSD) was used to examine the grain structure in long rods of ultrafine-grain (UFG) commercial-purity titanium produced for medical implants. The UFG material was obtained by equal channel angular pressing (ECAP) using a Conform scheme followed by rod drawing. The microstructure was found to be bimodal consisting of relatively coarse elongated grains containing well-developed substructure and ultrafine grains. The mean grain size was ~0.3 μm, and the fraction of high-angle boundaries was ~45%. The material had a strong <101¯0>-fiber texture. An analysis of the microstructure-properties relationship showed that the increase in material strength developed during severe plastic deformation resulted from grain refinement and substructure evolution in comparable measure.