Effect of strain rate on the mechanical properties of a gum metal with various microstructures

S Liu; Z.L Pan; Yonghao Zhao; Troy D Topping; Ruslan Valiev; X.Z Liao; E.J Lavernia; Y.T Zhu; Qiuming Wei

doi:10.1016/j.actamat.2017.04.052

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Effect of strain rate on the mechanical properties of a gum metal with various microstructures

Journal article

Peer reviewed

Effect of strain rate on the mechanical properties of a gum metal with various microstructures

S Liu, Z.L Pan, Yonghao Zhao, Troy D Topping, Ruslan Valiev, X.Z Liao, E.J Lavernia, Y.T Zhu and Qiuming Wei

Acta materialia, Vol.132, pp.193-208

06/15/2017

DOI: https://doi.org/10.1016/j.actamat.2017.04.052

Handle:

https://hdl.handle.net/20.500.12741/rep:4608

Abstract

Gum metal

Adiabatic shear banding

ECAP

Texture

EBSD

Grain refinement

In this work, a bulk gum metal (GM) was fabricated via arc melting from high purity powders. The ingots were first extruded using a conventional route followed by equal channel angular pressing (ECAP). The mechanical behavior of the extruded GM and ECAP-processed GM was studied under both quasi-static and high strain rate compression conditions to evaluate the influence of strain rate. In addition, the associated mechanical anisotropy, or the lack thereof, was investigated through loading in different orientations with respect to the extrusion or ECAP direction. Precipitous stress drops were observed under dynamic compression of both extruded and ECAP-processed GM specimens when loading perpendicular to the extrusion direction. Adiabatic shear banding (ASB) was found to be associated with the precipitous stress drops on the dynamic stress-strain curves. The details of the ASBs were characterized by optical and scanning electron microscopy, with emphasis on electron backscattered diffraction (EBSD). The mechanisms responsible for the formation of ASB were examined both from thermal softening and geometrical softening perspectives. Significant microstructure refinement within ASBs was established, and a possible grain refinement mechanism was proposed. [Display omitted]

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Title: Effect of strain rate on the mechanical properties of a gum metal with various microstructures
Creators: S Liu - Nano Structural Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, People’s Republic of China
Z.L Pan - Department of Mechanical Engineering, University of North Carolina at Charlotte, NC, 28223-0001, USA
Yonghao Zhao - Nano Structural Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, People’s Republic of China
Troy D Topping
Ruslan Valiev - Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, Ufa, 450000, Russian Federation
X.Z Liao - School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW, 2006, Australia
E.J Lavernia - Department of Chemical Engineering and Materials Science, University of California, Davis, CA, 95616, USA
Y.T Zhu - Nano Structural Materials Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, People’s Republic of China
Qiuming Wei - Department of Mechanical Engineering, University of North Carolina at Charlotte, NC, 28223-0001, USA
Academic Unit: Mechanical Engineering Department
Publisher: Elsevier Ltd
Publication Details: 06/15/2017
Identifiers: 99257881177701671; https://hdl.handle.net/20.500.12741/rep:4608; https://doi.org/10.1016/j.actamat.2017.04.052
Language: English