Strong, Ductile, and Thermally Stable bcc-Mg Nanolaminates

Pathak, Siddhartha; Velisavljevic, Nenad; Baldwin, Jon K.; Jain, Manish; Zheng, Shijian; Mara, Nathan A.; Beyerlein, Irene J.

doi:10.1038/s41598-017-08302-5

Cited by 55 publications

(26 citation statements)

References 52 publications

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“…have shown that the bcc‐Mg structure may appear in Mg/Nb multilayers under ambient conditions. Pathak et al . have demonstrated that in 5 nm/5 nm Mg/Nb multilayers both phases adopted the same bcc lattice parameter < a >=0.3347 nm, whereas in 50 nm/50 nm multilayers the lattice parameters of Mg and Nb layers are similar to those of bulk.…”

Section: Theoretical Approach To Destabilization Of Hydrogen‐storage mentioning

confidence: 99%

Influence of Defects on the Stability and Hydrogen‐Sorption Behavior of Mg‐Based Hydrides

Novaković

Kurko

et al. 2019

ChemPhysChem

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This review deals with the destabilization methods for improvement of storage properties of metal hydrides. Both theoretical and experimental approaches were used to point out the influence of various types of defects on structure and stability of hydrides. As a case study, Mg, and Ni based hydrides has been investigated. Theoretical studies, mainly carried out within various implementations of DFT, are a powerful tool to study mostly MgH 2 based materials. By providing an insight on metalhydrogen bonding that governs both thermodynamics and hydrogen kinetics, they allow us to describe phenomena to which experimental methods have a limited access or do not have it at all: to follow the hydrogen sorption reaction on a specific metal surface and hydrogen induced phase transformations, to describe structure of phase boundaries or to explain the impact of defects or various additives on MgH 2 stability and hydrogen sorption kinetics. In several cases theoretical calculations reveal themselves as being able to predict new properties of materials, including the ways to modify Mg or MgH 2 that would lead to better characteristics in terms of hydrogen storage. The influence of ion irradiation and mechanical milling with and without additives has been discussed. Ion irradiation is the way to introduce a well-defined concentration of defects (Frankel pairs) at the surface and subsurface layers of a material. Defects at the surface play the main role in sorption reaction since they enhance the dissociation of hydrogen. On the other hand, ball-milling introduce defects through the entire sample volume, refine the structure and thus decrease the path for hydrogen diffusion. Two Severe Plastic Deformation techniques were used to better understand the hydrogenation/dehydrogenation kinetics of Mg-and Mg 2 Nibased alloys: Equal-Angular-Channel-Pressing and Fast-Forging. Successive ECAP passes leads to refinement of the microstructure of AZ31 ingots and to instalment therein of high densities of defects. Depending on mode, number and temperature of ECAP passes, the H-sorption kinetics have been improved satisfactorily without any additive for mass H-storage applications considering the relative speed of the shaping procedure. A qualitative understanding of the kinetic advanced principles has been built. Fast-Forging was used for a "quasiinstantaneous" synthesis of Mg/Mg 2 Ni-based composites. Hydrogenation of the as-received almost bi-phased materials remains rather slow as generally observed elsewhere, whatever are multiple and different techniques used to deliver the composite alloys. However, our preliminary results suggest that a synergic hydrogenation / dehydrogenation process should assist hydrogen transfers from Mg/Mg 2 Ni on one side to MgH 2 / Mg 2 NiH 4 on the other side via the rather stable a-Mg 2 NiH 0.3 , acting as in-situ catalyser.

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Section: Theoretical Approach To Destabilization Of Hydrogen‐storage mentioning

confidence: 99%

Influence of Defects on the Stability and Hydrogen‐Sorption Behavior of Mg‐Based Hydrides

Novaković

Kurko

et al. 2019

ChemPhysChem

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“…The mechanical strength inferred from indentation hardness can be as high as 0.8 GPa when the layers are a few nanometers thick. 32 Pathak et al 33 also demonstrated an extremely high peak strength of 1.7 GPa of Mg/Nb multilayers with an individual layer thickness of 50 nm by micro-pillar compression.…”

Section: Introductionmentioning

confidence: 95%

Interface Facilitated Reorientation of Mg Nanolayers in Mg-Nb Nanolaminates

Chen

Gong

Shao

et al. 2019

JOM

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Mg/Nb nanolaminates synthesized through vapor deposition techniques exhibit high flow strength without conventional twinning in Mg. In this work, we investigated the influence of laminated microstructures on deformation mechanisms of Mg nanolayers. Using molecular dynamics simulations, we explored that (0001)-oriented Mg layers transform or re-orient to {1010}-oriented Mg layers through nucleation and growth of {1012} twins by atomic shuffling, instead of conventional {1012} twinning shear. Such a reorientation accommodates in-plane compressive strain and out-of-plane tensile strain when Mg/Nb laminates are subjected to compression parallel to the Mg/Nb interfaces. The nucleation of {1012} twins is promoted at the Mg/Nb interface due to the structural change associated with the glide of interface dislocations. The growth of {1012} twins is accomplished through migration of basal-prismatic boundaries via nucleation and glide of onelayer and two-layer disconnections associated with atomic shuffling. The results shed light on improving mechanical properties of hexagonal closepacked metals employing laminated structures.

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“…On the other hand, the length scale dependent the fracture toughness of fcc/hcp NMMFS is also influenced by the transformation of lattice structures [15]. Due to the dimension induced phase transformation in Ru layer, the fcc/fcc Cu/Ru should possess a great deal of slip systems to accommodate plastic deformation; while, hcp Ru are difficult to deform due to few slip systems are available [21,115,116]. Accordingly, the difference in fracture toughness between fcc/hcp multilayers whether has structure transformation are summarized, as shown in Figure 17.…”

Section: Phase Transformation Enhanced Tougheningmentioning

confidence: 99%

Cracking and Toughening Mechanisms in Nanoscale Metallic Multilayer Films: A Brief Review

Zhou

Ren

et al. 2018

Applied Sciences

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Nanoscale metallic multilayer films (NMMFs) have captured scientific interests on their mechanical responses. Compared with the properties of monolithic films, multilayers possess unique high strength as the individual layer thickness reduces to the nanoscale, which is benefited from the plentiful hetero-interfaces. However, NMMFs always exhibit a low fracture toughness and ductility, which seriously hinders their practical applications. While there have been reviews on the strengthening and deformation mechanisms of microlaminate, rapid developments in nanotechnology have brought an urgent requirement for an overview focused on the cracking and toughening mechanisms in nanoscale metallic multilayers. This article provides an extensive review on the structure, standard methodology and fracture mechanisms of NMMFs. A number of issues about the crack-related properties of NMMFs have been displayed, such as fracture toughness, wear resistance, adhesion energy, and plastic instability. Taken together, it is hoped that this review will achieve the following two purposes: (1) introducing the size-dependent cracking and toughness performance in NMMFs; and (2) offer a better understanding of the role interfaces displayed in toughening mechanisms. Finally, we list a few questions we concerned, which may shed light on further development.

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Strong, Ductile, and Thermally Stable bcc-Mg Nanolaminates

Cited by 55 publications

References 52 publications

Influence of Defects on the Stability and Hydrogen‐Sorption Behavior of Mg‐Based Hydrides

Influence of Defects on the Stability and Hydrogen‐Sorption Behavior of Mg‐Based Hydrides

Interface Facilitated Reorientation of Mg Nanolayers in Mg-Nb Nanolaminates

Cracking and Toughening Mechanisms in Nanoscale Metallic Multilayer Films: A Brief Review

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