The response of dislocations, low angle grain boundaries and high angle grain boundaries at high strain rates

A new layered heterostructure composite material system (TC4 as front layer and 2024Al alloy as back layer) was developed and analyzed for its design and performance in terms of an enhanced absorption capability and anti-penetration behavior. The Florence model for energy absorption was modified, so that it can be utilized for the layered heterostructure composite material system with more efficacy. Numerical simulation through Ls-Dyna validated the analytical model findings regarding the energy absorption of the system and both were in good agreement. Results showed that two ductile materials with diverse properties, the hardness gradient and varied layer thickness joined together, specifically behaved like a unified structure and exhibited elastic collision after slight bending, which is possibly due to the decreased yield strength of the front layer and increased yield strength of the second layer. To validate the analytical and numerical findings, the samples of the layered heterostructure composite material system were subjected to a SHPB (Split Hopkinson pressure bar) compression test. The deformation behavior was analyzed in the context of the strain energy density and stain rate sensitivity parameter at different strain rates. The encouraging results proposed that two ductile materials with a hardness gradient can be used as an alternate structure instead of a brittle–ductile combination in a layered structure.

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“…in stress, leading to material rupture. This deformation pattern shows the increased load bearing capability and enhanced ductility [28].…”

Section: Resultsmentioning

confidence: 88%

Design and Performance of Layered Heterostructure Composite Material System for Protective Armors

Siddique

Hussain

et al. 2023

Materials

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“…Plastic deformations are easy to achieve at high pressures. However, for the HPHT consolidation of HfC, the critical challenge is to solve the quick decrease in shear stress as the temperature increases by introducing a large amount of plastic deformations Figure b presents the large field-of-view bright-field STEM micrographs of the a /2⟨110⟩ dislocated structures of HfC consolidated at 15 GPa and 1700 °C.…”

Section: Resultsmentioning

confidence: 99%

“…However, for the HPHT consolidation of HfC, the critical challenge is to solve the quick decrease in shear stress as the temperature increases by introducing a large amount of plastic deformations. 52 Figure 3b presents the large field-of-view bright-field STEM micrographs of the a/2⟨110⟩ dislocated structures of HfC consolidated at 15 GPa and 1700 °C. These desirable dislocations are uniformly distributed in the crystal grains, which suggests that high temperatures can enhance atomic long-range diffusion and increase the mobility of high-density dislocations.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Achieving Dislocation Strengthening in Hafnium Carbide through High Pressure and High Temperature

et al. 2021

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Dislocations profoundly impact the mechanical behavior of materials. High dislocation density induced strengthening is easily achieved in metallic materials, but it is a challenge in ceramics. Here, we highlight the dislocation engineering of an ultrahigh-temperature ceramic, hafnium carbide (HfC), by high-pressure and high-temperature (HPHT) consolidation. The microstructure and temperature-dependent high-pressure consolidation behaviors were systematically investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Our results reveal that pressure-induced intergranular strains promote the generation of high-density dislocations in multiple orientations near grain boundaries and finally enhance the hardness and oxidation resistance of the HfC ceramic. These findings elucidate that dislocation strengthening can be achieved in ultra-high-temperature ceramic HfC, which offers crucial insights for the design and synthesis of advanced ceramic materials.

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“…Sun et al [57] used surface mechanical abrasive treatment (SMAT) to reveal that the grain refinement process of WE43 magnesium alloys consisted of three transitional stages: dislocation cell and stacking, ultrafine subgrain, and randomly oriented nanoparticles. Moreover, Liu et al [58] found that dislocations formed LAGBs at high strain rates by compressing steel with a shock wave generated by an air gun, and that LAGBs tended to transform into HAGBs accompanied by grain rotation. The SFs are more effective for dislocation accumulation and blocking [16].…”

Section: Refinement Mechanisms By Sfs At High Strain Ratesmentioning

confidence: 99%

Effect of 1wt%Zn Addition on Microstructure and Mechanical Properties of Mg-6Er Alloys under High Strain Rates

Ren²,

Kang³

et al. 2022

Metals

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In this study, we investigated the high strain rate response of Mg-6wt%Er alloys with 1wt%Zn addition by split Hopkinson pressure bar (SHPB) tests in a range of 900–2500 s−1. Their related microstructures were also characterized by optical microscopy (OM), scanning electron microscopy (SEM), electron back-scattering diffraction (EBSD), and transmission electron microscopy (TEM). In particular, the twinning and stacking faults (SFs) in Mg-6Er and Mg-6Er-1Zn alloys are characterized, and the interactions between twin/SFs and dislocations are analyzed in detail. Compared with twins, the dispersed and dense SFs seem to more readily interact with dislocations, resulting in the enhancement of the strength of alloys. Especially at a high strain rate of 1450 s−1, dislocations are prone to tangle around the twins and SFs, forming low-angle grain boundaries (LAGBs). The addition of Zn in Mg-6Er can make LAGBs more easily transform into high-angle grain boundaries (HAGBs) due to the existence of SFs.

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The response of dislocations, low angle grain boundaries and high angle grain boundaries at high strain rates

Cited by 95 publications

References 67 publications

Design and Performance of Layered Heterostructure Composite Material System for Protective Armors

Design and Performance of Layered Heterostructure Composite Material System for Protective Armors

Achieving Dislocation Strengthening in Hafnium Carbide through High Pressure and High Temperature

Effect of 1wt%Zn Addition on Microstructure and Mechanical Properties of Mg-6Er Alloys under High Strain Rates

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