Dynamic shear localization of a titanium alloy under high-rate tension characterized by x-ray digital image correlation

Journal Article · Thu Mar 15 00:00:00 EDT 2018 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2018.01.011· OSTI ID:22804917

Wu, S.Y., E-mail: [e-mail] ^[1]; The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610207 ^[2]; Bie, B.X., E-mail: [e-mail]; Fan, D., E-mail: [e-mail] ^[3]; Sun, T., E-mail: [e-mail]; Fezzaa, K., E-mail: [e-mail] ^[4]; Feng, Z.D., E-mail: [e-mail] ^[1]; The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610207 ^[2]; Huang, J.Y., E-mail: [e-mail] ^[3]; Luo, S.N., E-mail: [e-mail] ^[1]; The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610207 ^[2]

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1. Key Laboratory of Advanced Technologies of Materials, Ministry of Education, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)
2. (China)
3. The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610207 (China)
4. Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

Highlights: • First systematic error analyses for XDIC • First XDIC study of Ti-6Al-4V under dynamic tension • Deformation mode transition induces dynamic ductility decrease. • Dynamic shear localization due to rate-dependent microvoid coalescence process. - Abstract: Dynamic and quasi-static tension experiments are conducted on Ti-6Al-4V alloys, with in situ, synchrotron-based, high-speed, x-ray phase contrast imaging implemented to characterize the dynamic deformation and fracture process of Ti alloys at the Advanced Photon Source. X-ray digital imaging correlation (XDIC) is applied for strain field mapping. The size distribution of x-ray speckles are quantified via a morphological analysis, with a mean of ∼20 μm. Systematic error analyses of displacement and strain field measurements are firstly conducted for XDIC, and demonstrate that the displacement and strain errors can be controlled below 0.01 pixel and 0.1%, respectively. Mesoscale strain characteristics measured via XDIC are consistent with and reveal mechanisms for the bulk-scale stress–strain responses. Under dynamic tension, a sharp transition to strain softening occurs when the bulk strain exceeds about 0.04, which leads to a lower dynamic fracture strain (0.08) than the quasi-static one (0.1). The corresponding strain filed mapping demonstrates that shear deformation localizations grow and coalesce rapidly into a narrow shear deformation band under dynamic loading, while tensile deformation and necking progresses gradually under quasi-static loading. Scanning electron microscopy shows that void nucleation occurs mainly at the interface of α and β phases for both quasi-static and dynamic tension. However, microvoids coalesce preferentially along colony boundaries or the boundary α phase under quasi-static tension, but along the maximum shear stress direction (across colonies) under dynamic tension. Fractography of recovered samples also shows consistent features.

• OSTI ID: 22804917
• Journal Information: Materials Characterization, Vol. 137; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ADVANCED PHOTON SOURCE
ALUMINIUM COMPOUNDS
CORRELATIONS
DEFORMATION
DISTRIBUTION
DUCTILITY
INTERFACES
SCANNING ELECTRON MICROSCOPY
STRAIN SOFTENING
STRESSES
TITANIUM ALLOYS
VANADIUM COMPOUNDS