Shear characteristics and failure mechanism of laser metal deposition GH4169 at different strain rates

LI Xiaolong; LI Penghui; GUO Weiguo; YUAN Kangbo

doi:10.11883/bzycj-2019-0254

Volume 40 Issue 8

Aug. 2020

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LI Xiaolong, LI Penghui, GUO Weiguo, YUAN Kangbo. Shear characteristics and failure mechanism of laser metal deposition GH4169 at different strain rates[J]. Explosion And Shock Waves, 2020, 40(8): 083101. doi: 10.11883/bzycj-2019-0254

Citation:

LI Xiaolong, LI Penghui, GUO Weiguo, YUAN Kangbo. Shear characteristics and failure mechanism of laser metal deposition GH4169 at different strain rates[J]. Explosion And Shock Waves, 2020, 40(8): 083101. doi: 10.11883/bzycj-2019-0254

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Shear characteristics and failure mechanism of laser metal deposition GH4169 at different strain rates

doi: 10.11883/bzycj-2019-0254

School of aeronautics, Northwestern Polytechnical University, Xi’an 710072, Shaanxi, China

Received Date: 2019-06-24
Rev Recd Date: 2020-01-03
Publish Date: 2020-08-01

Abstract

Abstract

In order to accurately and reliably test the dynamic shear characteristics of laser metal deposition GH4169 on a traditional split Hopkinson pressure bar, this study compared the three different dynamic shear sample forms and dimensions to the shear zone stress based on numerical simulation. The influence of the distribution shows that the shear stress of the shear zone of the double shear specimen after optimization is dominant, and the dynamic shear test of approximate pure shear can be realized. Using this specimen form, the shear stress-strain curves of LMD GH4169 specimens with different orientations (scanning direction, deposition direction) at different strain rates were systematically tested, and the specimens were analyzed by SEM. The results show that: (1) the specimen used in this paper has high shear purity and uniform thickness distribution along the shear zone width, which can better obtain the dynamic shear properties of the material; (2) the shear stress-shear strain curves obtained from the experiment were analyzed. It is found that the material shows unobvious anisotropy in the scanning path direction and deposition direction. With the increase of strain rate, it has obvious strain rate strengthening effect; the uniaxial compression and dynamic shear stress-strain curves were simultaneously converted into equivalent stress-strain curves; the comparison confirms that the specimen form in this manuscript can exactly reflect the shear properties of the material; (3) through the microscopic analysis of the shear deformation of LMD GH4169, the size and depth of the fracture dimple decrease as the strain rate increases, and the toughness decreases. The shear failure is easy under a smaller deformation. Initial microscopic defects are likely to cause dynamic shear failure of the material.
- laser metal eeposition,
- GH4169,
- strain rate,
- dynamic shear,
- fracture mechanism

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References(17)

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