| Summary: | Recently, severe plastic deformation of alloys under cold conditions has been experimentally investigated to develop refined microstructures. The present study proposed to demonstrate the feasibility of applying cold deformation to a β-solution treated near β-Ti alloy. To be specific, the evolution of microstructure and mechanical properties of a β-solution treated near β-Ti alloy subjected to unidirectional 20% cold rolling were investigated. Results showed that long cracks formed in the 20% cold rolled sample. Meanwhile, two types of deformation-inducted α′ martensite have been observed in cold-rolled β matrix, namely, acicular α′ martensite with an orientation relationship of (12¯10)α′//(111)β with β matrix, and deformed (irregular shape) α′ martensite without coordinating orientation relationship. The formation of cracks was mainly related to the pre-existing α′ plate, and the micro-crack was prone to occur in α′ plates and propagate to β matrix. The microstructure characteristics result in poor ductility and low ultimate strength in the cold-rolled sample. Lastly, the lattice distortion and {101¯2}1¯011 α′-twinning were also characterized in the deformed α′ plates.
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