A combination of transmission electron microscopy and scanning electron microscopy was used to study torsion deformation and fracture behaviors of Ti–5Al–5Mo–5V–3Cr–1Zr (Ti–55531) alloy with lamellar microstructure (LM) and bimodal microstructure (BM) at ambient temperature. The results indicate that torsion strength and ductility of BM are significantly lower than those of LM. Shear bands and dislocation tangles are mainly observed in secondary α (αs) lamellae for both microstructures. Furthermore, straight slip lines only exist in equiaxed primary α (αp) phase. The coarsening αs lamellae dominate the deformation of LM, while the deformation of BM is greatly controlled by equiaxed αp phase. Fractographs of LM and BM show a mixture fracture mechanism of microvoid coalescence and transgranular shear fracture. Besides, BM exhibits intergranular fracture mechanism. Thus, Ti–55531 alloy with BM is easier to be damaged than LM during torsion loading.

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dislocation tangles torsion deformation lm transgranular ti55531 alloy coarsening inf locpostsinf lamellae fracture behaviors bands microvoid coalescence primary inf locpostpinf fracture mechanism transmission electron microscopy lamellar microstructure ductility

Qian Li, Shewei Xin,Chaowen Huang, Yongqing Zhao, Weidong Zeng, Wei Zhou,.Effect of microstructure on torsion properties of Ti–5Al–5Mo–5V–3Cr–1Zr alloy. 682 (0),202-210.

Qian Li, et al."Effect of microstructure on torsion properties of Ti–5Al–5Mo–5V–3Cr–1Zr alloy" 682

Qian Li, Shewei Xin,Chaowen Huang, Yongqing Zhao, Weidong Zeng, Wei Zhou,"Effect of microstructure on torsion properties of Ti–5Al–5Mo–5V–3Cr–1Zr alloy"