An investigation of the tensile deformation mechanism of a high-oxygen Ti2448 alloy fabricated by powder metallurgy by use of the in-situ EBSD method

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Ti2448 alloy fabricated by powder metallurgy using elemental powders of Ti, Nb, Zr and Sn exhibits good ductility but a high content of oxygen, and very limited work hardening in the tensile test. Its deformation mechanism is investigated by in-situ EBSD test conducted in an SEM equipped with a dynamic tensile stage. The results indicate that both dislocation slide and stress-induced phase transformation contribute to the plastic deformation of the alloy. Subsequent to yielding (after 3% of strain), β phase grains with preferential orientation 113β//X-axis tend to be transformed into α" martensite phase, which significantly reduces the plastic deformation caused by the dislocation slide and therefore leads to low work hardening.