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

Abstract

Dynamic and quasi-static tension experiments are conducted on Ti-6A1-4V 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 dynamicmore » 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.« less

Authors:

Wu, S. Y. ^[1]; Bie, B. X. ^[2]; Fan, D. ^[2]; Sun, T. ^[3]; Fezzaa, K. ^[3]; Feng, Z. D. ^[1]; Huang, J. Y. ^[2]; Luo, S. N. ^[1]

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+ Show Author Affiliations

1. Southwest Jiaotong Univ., Sichuan (People's Republic of China); The Peac Institute of Multiscale Sciences, Sichuan (People's Republic of China)
2. The Peac Institute of Multiscale Sciences, Sichuan (People's Republic of China)
3. Argonne National Lab. (ANL), Argonne, IL (United States)

Publication Date:

Tue Jan 09 00:00:00 EST 2018

Research Org.:

Argonne National Lab. (ANL), Argonne, IL (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES); National Natural Science Foundation of China (NSFC)

OSTI Identifier:

1461331

Alternate Identifier(s):

OSTI ID: 1496379

Grant/Contract Number:  

AC02-06CH11357

Resource Type:

Accepted Manuscript

Journal Name:

Materials Characterization

Additional Journal Information:

Journal Volume: 137; Journal Issue: C; Journal ID: ISSN 1044-5803

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; Titanium alloy; high-rate tension; x-ray phase contrast imaging; digital image correlation; shear deformation band