Oxygen effect on bending behavior of a zirconium based bulk metallic glass

Teixeira, Claudio Alexandre Barros; Silva, R.V. da; Pereira, Leonardo T.; Oliveira, Marcelo Falção de

doi:10.1016/j.jnoncrysol.2020.119966

Cited by 8 publications

(1 citation statement)

References 32 publications

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“…Chu et al [39,40], who worked on the Zr 55 Cu 30 Al 10 Ni 5 composition, observed that a glass including ductile non-spherical TiNb crystals was much more prone to ductility than another one containing harder oxide particles, and thus highlighted the significant influence of the inclusion yield strength on both ductility and fracture toughness. More generally, literature reports that oxygen-containing phases lead to a small increase, or at the opposite a drastic reduction of the fracture toughness of these materials [52][53][54].…”

Section: Introductionmentioning

confidence: 99%

Crystalline defects in bulk metallic glasses: consequences on fracture toughness determination and ductility

Bernard¹,

Kéryvin²

2020

J. Phys.: Condens. Matter

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Dating back to the late 1980s, bulk metallic glasses (BMGs) are relatively new materials that exhibit exceptional mechanical properties (strength, hardness, fracture toughness, stored elastic energy …), compared to those of most crystalline metallic alloys. Their apparent brittleness under uniaxial loading, however, is still a major obstacle to their industrialization. Moreover, BMGs often contain crystalline defects developed, intentionally or not, during their complex and delicate elaboration. These flaws are known to affect their fracture toughness and their plastic behavior. This paper reviews twenty years of works about this subject on Zr-based BMGs that may contain a low volume fraction of crystalline defects of different natures, e.g. dendrites or spherulites, depending on the synthesis method. Dedicated experimental set-ups, mainly bending tests on notched beams, were developed to create in the specimen a proper pre-crack by fatigue and then load it monotonically up to fracture. The measured fracture toughness and the fractographic observations allow to conclude that these crystalline defects facilitate pre-cracking, but result in an embrittlement that is more or less significant depending on their type. The loading mode of the crack — mode I, II or mixed — as well as the temperature were shown to play a key role in crack initiation and propagation, whether steadily or catastrophically, in the BMG. By means of finite element computations analyses, explanations on how the crystalline flaws presence can affect fracture toughness and perturbate crack growth, under mode I and mode II, were proposed. Finally, the relevance of these experimental techniques as well as the link between crystalline defects, fracture toughness and their consequences on the ductility of a structural component are discussed.

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Section: Introductionmentioning

confidence: 99%

Crystalline defects in bulk metallic glasses: consequences on fracture toughness determination and ductility

Bernard¹,

Kéryvin²

2020

J. Phys.: Condens. Matter

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Effect of Yttrium Additions in Relation to Oxygen Content on Glass Formation in the Zr50Cu40Al10 Alloy

Pajor

Kozieł

Rutkowski

et al. 2020

Metall Mater Trans A

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The effect of yttrium additions on the glass formation of the Zr50Cu40Al10 alloy with high oxygen content was investigated. Unlike other reports showing the positive effect of alloying Zr-based alloys with a few percent of rare earth elements, we examined the Y-to-oxygen ratios. As calculated, a stoichiometric amount of yttrium (2808 at ppm) is required to bind all the oxygen (4212 at ppm) to form the Y2O3. Additionally, the influence of half (1404 at ppm) and double stoichiometric (5616 at ppm) levels of yttrium, with respect to the measured oxygen content to be bound was evaluated. The Y-doped alloys were synthesized by arc melting, followed by suction casting into copper molds with conical and rod cavities. The critical diameter of the undoped alloy was below 3 mm, while stoichiometric and double stoichiometric yttrium concentrations allowed to obtain 5 and 7 mm diameter glassy samples, respectively. Microstructure observations confirmed the scavenging effect of yttrium, leading to the formation of a cubic ($$ Ia\bar{3} $$ I a 3 ¯ space group) yttrium sesquioxide. The glass forming ability of the alloys was additionally determined based on differential thermal analysis, allowing to propose the best indicator for the studied Zr-Cu-Al alloys.

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Advancing Bulk Metallic Glass Formation: Utilizing Rare-Earth Elements in Zr-Based Alloys

Pajor,

Gondek,

Tyrała

et al. 2023

Metall Mater Trans A

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Zr-based bulk metallic glasses (BMGs) are characterized by excellent glass-forming ability, combined with superior mechanical properties. However, oxygen impurities degrade both these aspects as oxides serve as heterogeneous nucleation sites during solidification. Rare-earth elements (REEs) are known to be good oxygen scavengers, binding oxygen to less harmful forms. The most stable rare-earth oxide (REO) is M2O3, which occurs in three polymorphic forms, depending on the radius of metal cation: cubic, hexagonal, and monoclinic. Here, we show the effect of Sc, Y, Lu, Nd, and Gd additions in relation to the oxygen content on the glass-forming ability of the Zr52.5Cu17.9Ni14.6Al10Ti5 alloy. Microscopic observations (SEM) supported by chemical analysis (EDS, WDS), structure identification (XRD), and thermal analysis (DTA) were carried out. The critical diameter for glass formation (Dc) in the high oxygen alloy doped with cubic oxide-forming elements (Sc, Y, and Lu) can be even higher (Dc = 9 mm) compared to the undoped alloy synthesized from low oxygen components. Therefore, we have demonstrated that it is feasible to produce BMG using low-purity constituents with REE-based oxygen scavengers. This bridges the gap between laboratory development and cost-effective commercial applications. Graphical Abstract

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Oxygen effect on bending behavior of a zirconium based bulk metallic glass

Cited by 8 publications

References 32 publications

Crystalline defects in bulk metallic glasses: consequences on fracture toughness determination and ductility

Crystalline defects in bulk metallic glasses: consequences on fracture toughness determination and ductility

Effect of Yttrium Additions in Relation to Oxygen Content on Glass Formation in the Zr50Cu40Al10 Alloy

Advancing Bulk Metallic Glass Formation: Utilizing Rare-Earth Elements in Zr-Based Alloys

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