Influence of ECAP routes on the microstructure and properties of pure Ti

Equal channel angular pressing (ECAP) is an innovative technique that can produce bulk ultrafine-grained (UFG) materials in product forms large enough for structural applications. It is well known that ECAP route, defined by the sequence of orientations of the billets relative to the die during the iterative ECAP passes, significantly affects the microstructural development of the work piece. Studies reported in the literature have so far focused on fcc metals such as Al and Cu. In this work, we have studied the influence of ECAP routes on the microstructures and properties of hcp commercially-pure Ti. Three ECAP routes, conventionally defined as B_A, B_C and C, were used to process the Ti billets. Surface quality, microstructures, microhardness, tensile properties, anisotropy, and thermal stability were studied. The route B_C is shown to be the best route for processing hcp Ti.