Influences of nanotwin volume fraction on the ballistic performance of coarse-grained metals

Ouyang, Q.D.; Weng, George J.; Soh, Ai‐Kah; Guo, Xiang

doi:10.1016/j.taml.2017.09.012

Cited by 4 publications

(3 citation statements)

References 21 publications

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“…The limit velocity V b is defined as the lowest impact velocity with which the bullet fails the entire specimen, i.e., the bullet initiates microcracks to penetrate the entire specimen [ 48 , 49 ]. Higher V b means stronger ability to resist failure under the ballistic impact.…”

Section: Resultsmentioning

confidence: 99%

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Ballistic Performance of Nanostructured Metals Toughened by Elliptical Coarse-Grained Inclusions: A Finite Element Study with Failure Analysis

et al. 2018

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Bimodal nanostructured (NS) metals, in which the nano-grains or ultrafine grains serve as matrix phase while the coarse grains serve as toughening phase, can synergize the overall strength and ductility to achieve excellent bullet-proof performance. Because of the extrusion process in the fabrication, the coarse-grained (CG) inclusions are elongated in the extrusion direction and elliptical CG inclusions with different aspect ratios form. The shape, distribution, and volume fraction of these elliptical CG inclusions can all have significant influence on the overall ballistic performance. In this study, the strain gradient plasticity model together with the Johnson–Cook failure criterion is employed to investigate the ballistic performance of the bimodal NS Cu with elliptical CG inclusions. Our results show that the ballistic performance can be improved by increasing the aspect ratio of the elliptical CG inclusions. Furthermore, the staggered distribution of the elliptical CG inclusions will decrease the overall ability of the material to resist failure, but it will improve its overall ability to resist deformation. The larger stagger degree of elliptical CG inclusions can weaken their shape effects on the limit displacement.

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Section: Resultsmentioning

confidence: 99%

“…The central zone of the specimen is hit directly and thus has a displacement. We define the maximum of the absolute value of this displacement as limit displacement— D b [ 48 , 49 ]. Obviously, the smaller the D b is, the smaller deformation the specimen has and the larger its deformation resistance is.…”

Section: Resultsmentioning

confidence: 99%

Ballistic Performance of Nanostructured Metals Toughened by Elliptical Coarse-Grained Inclusions: A Finite Element Study with Failure Analysis

et al. 2018

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“…The Johnson-Cook model [32,45] is very extended when strain rate and thermal softening or pressure are important factors to be considered in the fracture process, i.e., ballistic applications [46][47][48][49][50] and blast loadings [51][52][53][54]. This model defines a damage parameter D expressed by Equation 2, where ∆ε p is the equivalent plastic strain rate and ε R p the equivalent plastic strain to failure, which is dependent on the strain rate, temperature and pressure, as Equation 3shows.…”

Section: Johnson-cook Modelmentioning

confidence: 99%

Distinct Fracture Patterns in Construction Steels for Reinforced Concrete under Quasistatic Loading— A Review

Guerra

Gálvez

Cendón

et al. 2018

Metals

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Steel is one of the most widely used materials in construction. Nucleation growth and coalescence theory is usually employed to explain the fracture process in ductile materials, such as many metals. The typical cup-cone fracture pattern has been extensively studied in the past, giving rise to numerical models able to reproduce this pattern. Nevertheless, some steels, such as the eutectoid steel used for manufacturing prestressing wires, does not show this specific shape but a flat surface with a dark region in the centre of the fracture area. Recent studies have deepened the knowledge on these distinct fracture patterns, shedding light on some aspects that help to understand how damage begins and propagates in each case. The numerical modelling of both fracture patterns have also been discussed and reproduced with different approaches. This work reviews the main recent advances in the knowledge on this subject, particularly focusing on the experimental work carried out by the authors.

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Retrieving Grain Boundaries in 2D Materials

Zhou

et al. 2022

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provides a feasible pathway to achieving improved ductility for brittle alloys and ceramics. [9][10][11][12][13] Moreover, GBs prove to be capable of improving the minority carrier collection in polycrystalline CdTe and Cu(In,Ga)Se 2 solar cells, leading to higher efficiencies than their single-crystal counterparts by 24% and 69%, respectively. [14,15] The GB effects tend to be enhanced in 2D materials, owing to unique space dimensionality and reduced Coulomb screening. In that case, GBs can not only directly disrupt the crystalline order, but also become all surface-accessible to permit substantial interactions with external species, providing a profound opportunity to enrich 2D materials with novel attributes.GB engineering at the atomic scale results in not only robust nanostructures but also the modification of material characteristics, which is often unachievable in pristine 2D materials. High-resolution characterization images have revealed that GBs in 2D materials are constructed by well-ordered periodic arrays of dislocation cores. [16,17] Compared with point defects (such as vacancies and impurities) that are highly vulnerable to chemical passivation or thermal annealing, GBs have conserved coordination environments, which are structurally more robust and cannot be eliminated by local structural rearrangements. [18,19] The structural diversity of GBs, enabled by flexible combinations of dislocations and varied chemical makeup, [20,21] adds extra tunability to their properties. The mechanical and electronic performances of 2D materials have been shown to depend on detailed GB microstructures. [22] Novel functionalities pertaining to GBs, such as magnetic centers, [23] catalytic sites, [24] and single photon sources, [25] have been reported. Therefore, engineering 2D materials based on GBs has opened a way to achieving a range of complementary properties through structural and compositional controls.Despite encouraging researches on the GB engineering of 2D materials, the application of GBs in functional devices remains far from being deployable, largely limited by the absence of precise control over detailed GB microstructures. Moreover, the limited understanding of the formation mechanism and structure-property relationships of GBs has also retarded the progress of this field. In this review, we examine the diverse compositions and microstructures of GBs in a range of common 2D materials, from elemental (e.g., graphene, borophene, and black phosphorus) to compound ones (e.g., h-BN, MoS 2 , and ReS 2 monolayers). The kinetic growth mechanism and energy evolution of GBs against variation in The coalescence of randomly distributed grains with different crystallographic orientations can result in pervasive grain boundaries (GBs) in 2D materials during their chemical synthesis. GBs not only are the inherent structural imperfection that causes influential impacts on structures and properties of 2D materials, but also have emerged as a platform for exploring unusual physics and functionalities stemming from dra...

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Influences of nanotwin volume fraction on the ballistic performance of coarse-grained metals

Cited by 4 publications

References 21 publications

Ballistic Performance of Nanostructured Metals Toughened by Elliptical Coarse-Grained Inclusions: A Finite Element Study with Failure Analysis

Ballistic Performance of Nanostructured Metals Toughened by Elliptical Coarse-Grained Inclusions: A Finite Element Study with Failure Analysis

Distinct Fracture Patterns in Construction Steels for Reinforced Concrete under Quasistatic Loading— A Review

Retrieving Grain Boundaries in 2D Materials

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