超快扫描量热揭示铝基金属玻璃过冷液态:接近液体脆度的理论极限（英文）

铝基非晶合金具有密度低、强度高、耐腐蚀等诸多优异性能;然而,铝基非晶合金形成能力差,一般需要非常高的冷却速率,这限制了铝基非晶合金的应用.玻璃形成理论认为形成能力与过冷液体密切相关.但在一般升温测量时,铝基非晶合金不显示玻璃转变或过冷液体,而是直接变成晶态.目前为止,关于铝基非晶合金的玻璃转变和过冷液体属性仍然是未知的.本文采用超快速差热分析方法(Flash DSC)使得升温速度达到10000 K s^-1,测量了20余种常见铝基非晶合金的玻璃转变行为和过冷液体特征.发现铝基非晶合金普遍具有很高的液体脆度系数(m),其中某些成分m>160,已经接近理论上预测的脆度系数上限m^175.通过系统研究这些成分的形成能力,发现铝基非晶合金的玻璃形成能力与脆度系数成反相关,而且这种相关不是线性的.只有m<100时,降低m才会对玻璃形成能力有明显影响;相反, m>100的玻璃形成力普遍较弱,而且随m变化不显著.因此,过高的液体脆度系数可能是铝基非晶合金形成能力差的一个重要原因.     

Fabrication and Properties of Micro‐ and Nanoscale Metallic Glassy Wires: A Review

A large number of metallic glasses (MGs) with high mechanical and functional performance that cannot be achieved by traditional metals in various alloy systems have been developed. At the same time, people realized that micro‐ and nanoscale wires can improve properties and extend functionality of bulk materials. Therefore, intensive effort has been made to fabricate micro‐ and nanoscale MG wires, and study their mechanical and physical behavior to achieve high performance. This article reviews fabrication, properties and applications of the wires, and presents technical and theoretical challenges, which must be tackled to achieve high‐performance MG wire devices and understand physical mechanisms of mechanical and functional behaviors of the wires.

     

Al基块体金属玻璃的研究进展

Al基金属玻璃具有高强度、高韧性、良好的耐蚀性,特别是其比强度高达330kN·m/kg,作为新结构材料在航空航天领域具有潜在的应用前景。近年不仅研发出了具有大过冷液相区以及能形成块体金属玻璃的Al基合金,还通过粉体温热固化成形工艺实现了Al基金属玻璃的大块体化,推动了其在实际生产中的应用。简述了有关Al基金属玻璃合金的玻璃形成能力、过冷液体热稳定性、力学性能及其粉末烧结体的组织和性能等方面的最新研究进展,并对其发展存在的问题进行了探讨。     

Bulk Metallic Glasses with Functional Physical Properties

In this review, we report on the formation of a variety of novel, metallic, glassy materials that might well have applications as functional materials. The metallic glasses, with excellent glass‐forming ability, display many fascinating properties and features such as excellent wave‐absorption ability, exceptionally low glass‐transition temperatures (～35–60 °C) approaching room temperature, ultralow elastic moduli comparable to that of human bone, high elasticity and high strength, superplasticity and polymer‐like thermoplastic formability near room temperature, an excellent magnetocaloric effect, hard magnetism and tunable magnetic properties, heavy‐fermion behavior, superhydrophobicity and superoleophobicity, and polyamorphism, all of which are of interest not only for basic research but also for technological applications. A strategy based on elastic‐moduli correlations for fabrication of bulk metallic glasses (BMGs) with controllable properties is presented. The work has implications in the search for novel metallic glasses with unique functional properties, for advancing our understanding of the nature and formation of glasses, and for extending the applications of the materials.     

Nanostructured Composite Materials with Improved Deformation Behavior

The recent progress in the development of nanostructured composites is described for Zr‐base multicomponent alloys as a typical example for such materials. These advanced composite materials are attractive candidates for structural as well as functional applications. The combination of high strength with high elastic strain of fully nanocrystalline and glassy alloys renders them quite unique in comparison to conventional (micro‐)crystalline materials. However, one major drawback for their use in engineering applications is the often limited macroscopic plastic deformability, despite the fact that some of these alloys show perfectly elastic‐plastic deformation behavior. To improve the room temperature ductility of either fully nanocrystalline or amorphous alloys, the concept of developing a heterogeneous microstructure combining a glassy or nanostructured matrix with second‐phase particles with a different length‐scale, has recently been employed. This review describes the composition dependent metastable phase formation in the Zr‐(Ti/Nb)‐Cu‐Ni‐Al alloy system, which in turn alters the mechanical properties of the alloys. We emphasize the possibilities to manipulate such composite microstructures in favor of either strength or ductility, or a combination of both, and also discuss the acquired ability to synthesize such in‐situ high‐strength composite microstructures in bulk form through inexpensive processing routes.     

Microalloyed medium-entropy alloy (MEA) composite nanolattices with ultrahigh toughness and cyclability

Three-dimensional nanolattices have recently emerged as an effective strategy to achieve high strength at low densities, by harnessing the combination of rationally designed topologies and nanoscale size effects [1], [2], [3], [4], [5]. However, most metallic and ceramic nanolattices show an ineludible deterioration of mechanical properties upon repeated loading due to localized brittle fracture. Here, by development and deposition of CoCrNiTi_0.1 microalloyed medium-entropy alloy (MEA) with extra low stacking fault energy, we fabricated ultratough MEA-coated nanolattices that can exhibit unprecedented surface wrinkling under compression. Particularly, nanolattices with alloy film thickness ∼ 30 nm can repeatedly withstand strains exceeding 50% with negligible strut fracture, while the elastic polymer core promotes recoverability and structural integrity. Furthermore, owing to the high strength of the metallic film, our MEA composite nanolattices exhibited high energy absorption (up to 60 MJ m⁻³) and specific strength (up to 0.1 MPa kg⁻¹ m³), offering a plethora of robust micro/nano-mechanical and functional applications.     

Bulk Glassy Alloys: Historical Development and Current Research

This paper reviews the development of current research in bulk glassy alloys by focusing on the trigger point for the synthesis of the first bulk glassy alloys by the conventional mold casting method. This review covers the background, discovery, characteristics, and applications of bulk glassy alloys, as well as recent topics regarding them. Applications of bulk glassy alloys have been expanding, particularly for Fe-based bulk glassy alloys, due to their unique properties, high glass-forming ability, and low cost. In the near future, the engineering importance of bulk glassy alloys is expected to increase steadily, and continuous interest in these novel metallic materials for basic science research is anticipated.     

Nanosecond Laser “Pulling” Patterning of Micro–Nano Structures on Zr-Based Metallic Glass

Flexible and controllable fabrication of micro–nano structures on metallic glasses (MGs) endow them with more functional applications, but it is still challenging due to the unique mechanical, physical, and chemical properties of MGs. In this study, inspired by a new physical phenomenon observed in the nanosecond laser–MG interaction (i.e., the surface structure is transformed from the normally observed microgroove into the micro–nano bulge at a critical peak laser power intensity), a nanosecond laser “pulling” method is proposed to pattern the MG surface. The formation mechanism and evolution of the micro–nano bulge are investigated in detail, and accordingly, various micro–nano structures including the unidirectional stripe, pillar, cross-hatch patterns, “JLU”, circle, triangle, and square, are derived and created on the MG surface, which affects the surface optical diffraction. Overall, this study provides a highly flexible and controllable method to fabricate micro–nano structures on MGs.     

Atomic-level structure and structure-property relationship in metallic glasses

The structure of metallic glasses (MGs) has been a long-standing mystery. On the one hand, MGs are amorphous materials with no long-range structural order; on the other hand, topological and chemical short-to-medium range order is expected to be pronounced in these alloys, due to their high atomic packing density and the varying chemical affinity between the constituent elements. The unique internal structure of MGs underlies their interesting properties, which render MGs potentially useful for various applications. While more and more glass-forming alloys have been developed in recent years, fundamental knowledge on the structural aspect of MGs remains seriously lacking. For example, how atoms pack on the short-to-medium range, how the structure differs in different MGs and changes with composition, temperature, and processing history, and more importantly, how the structure influences the properties of MGs, are still unresolved questions. In this paper, we review the tremendous efforts over the past 50 years devoted to unraveling the atomic-level structure of MGs and the structural origin of their unique behaviors. Emphasis will be placed on the progress made in recent years, including advances in structural characterization and analysis of prototypical MGs, general structural models and fundamental principles, and the correlations of thermodynamic, kinetic, and mechanical properties with the MG structures. Some widely observed property-property correlations in MGs are also examined from the structural perspective. The insights summarized are shown to shed light on many intriguing behaviors of the MG-forming alloys and expected to impact the development of MGs. Outstanding questions in this important research area will also be outlined.     

Micro injection of metallic glasses parts under ultrasonic vibration

This work investigates the evolution of structure and mechanical performance of metallic glasses(MGs)under a proposed rapid forming approach. Through the unique ultrasonic-assisted micro injection method, micro MGs parts with fine dimensional accuracy were successfully fabricated. The temperature during the micro injection is higher than the glass transition temperature and lower than the crystallization temperature. Differential scanning calorimeter curve and X-ray diffraction pattern show that the MGs micro parts keep the amorphous nature after the ultrasonic-assisted micro injection. Our results propose a novel route for the fast forming of MGs and have promising applications in the rapid fabrication of micro scale products and devices.     

Metallic glasses from “alchemy” to pure science: Present and future of design,processing and applications of glassy metals

Metallic glasses, first discovered a half century ago, are currently among the most studied metallic materials. Available in sizes up to several centimeters, with many novel, applicable properties, metallic glasses have also been the focus of research advancing the understanding of liquids and of glasses in general.Metallic glasses (MGs), called also bulk metallic glasses (BMGs) (or glassy metals, amorphous metals, liquid metals) are considered to be the materials of the future. Due to their high strength, metallic glasses have a number of interesting applications, for example as coatings. Metallic glasses can also be corrosion resistant. Metallic glasses, and the crystalline materials derived from them, can have very good resistance to sliding and abrasive wear. Combined with their strength – and now, toughness – this makes them ideal candidates for bio-implants or military applications. Prestigious Journals such as “Nature Materials”, “Nature” frequently publish new findings on these unusual glass materials. Moreover Chinese and Asian scientists have also been showing an interest in the study of metallic glasses.This review paper is far from exhaustive, but tries to cover the areas of interest as it follows: a short history, the local structure of BMGs and the glass forming ability (GFA), BMGs’ properties, the manufacturing and some applications of BMGs and finally, about the future of BMGs as valuable materials.     

Multifunctional Micro/Nanoscale Fibers Based on Microfluidic Spinning Technology

Superfine multifunctional micro/nanoscale fibrous materials with high surface area and ordered structure have attracted intensive attention for widespread applications in recent years. Microfluidic spinning technology (MST) has emerged as a powerful and versatile platform because of its various advantages such as high surface‐area‐to‐volume ratio, effective heat transfer, and enhanced reaction rate. The resultant well‐defined micro/nanoscale fibers exhibit controllable compositions, advanced structures, and new physical/chemical properties. The latest developments and achievements in microfluidic spun fiber materials are summarized in terms of the underlying preparation principles, geometric configurations, and functionalization. Variously architected structures and shapes by MST, including cylindrical, grooved, flat, anisotropic, hollow, core–shell, Janus, heterogeneous, helical, and knotted fibers, are emphasized. In particular, fiber‐spinning chemistry in MST for achieving functionalization of fiber materials by in situ chemical reactions inside fibers is introduced. Additionally, the applications of the fabricated functional fibers are highlighted in sensors, microactuators, photoelectric devices, flexible electronics, tissue engineering, drug delivery, and water collection. Finally, recent progress, challenges, and future perspectives are discussed.     

Nano-devitrification of glassy alloys

This overview paper summarizes a large number of data connected with nano-devitrification of metallic glassy and amorphous alloys on heating which form nanoscale crystalline or quasicrystalline particles. In some alloys this effect leads to formation of the nanocomposites with enhanced mechanical properties compared to fully glassy and crystalline alloys.     

A critical study of the emergence of glass and glassy metals as “green” materials

In 2008, The National Academy of Engineering (NAE – Washington, DC) identified the glass family (glasses, glass ceramics and glass composites) as central to many of the great engineering achievements of the twentieth century: the development of solid state lasers and optical glass fibers, biomaterials, glasses for imaging technologies, and glass films in microelectronic devices.The work reported in this paper discusses the importance of glass and metallic glasses as environmental friendly materials and also provide some points of view about the future influence of these materials for the related fields of industrial engineering and industrial ecology. The environmental capabilities of metallic glasses (MGs), which are considered to be among the important materials of the future, have not been sufficiently investigated. However, some aspects have yet to be done: the biocompatibility of most MGs, obtaining valuable MGs from waste materials, using MGs in green energy applications (solar cells and hydrogen production), using MGs in catalyst systems, as well as the possibility for using MGs in systems for retention and purification of dangerous pollutants and in the nuclear industry.     

Making metallic glasses plastic by control of residual stress

Metallic glasses, now that many compositions can be made in bulk, are of interest for structural applications exploiting their yield stress and yield strain, which are exceptionally high for metallic materials. Their applicability is limited by their near-zero tensile ductility resulting from work-softening and shear localization. Even though metallic glasses can show extensive local plasticity, macroscopically they can effectively be brittle, and much current research is directed at improving their general plasticity. In conventional engineering materials as diverse as silicate glasses and metallic alloys, we can improve mechanical properties by the controlled introduction of compressive surface stresses. Here we demonstrate that we can controllably induce such residual stresses in a bulk metallic glass, and that they improve the mechanical performance, in particular the plasticity, but that the mechanisms underlying the improvements are distinct from those operating in conventional materials.     

大块非晶形成合金液体的热物理性能与玻璃形成能力

大块非晶合金由于其优异的性能而成的具有很大潜力的新材料，而合金的玻璃形成能力（GFA）的大小是能否获得大块非晶合金的根本所在。因此研究合金的玻璃形成能力成为材料科学领域重要的研究课题。本文从液体热物理性能出发，结合在这些方面所做的研究工作对大块非晶形成合金液体的玻璃形成能力做了一些探讨，希望对大块非晶合的研究有所裨益。     

Chemically complex intermetallic alloys: A new frontier for innovative structural materials

Intermetallic materials are bestowed by diverse ordered superlattice structures together with many unusual properties. In particular, the advent of chemically complex intermetallic alloys (CCIMAs) has received considerable attention in recent years and offers a new paradigm to develop novel metallic materials for advanced structural applications. These newly emerged CCIMAs exhibit synergistic modulations of structural and chemical features, such as self-assembled long-range close-packed ordering, complex sublattice occupancy, and interfacial disordered nanoscale layer, potentially allowing for superb physical and mechanical properties that are unmatched in conventional metallic materials. In this paper, we critically review the historical developments and recent advances in ordered intermetallic materials from the simple binary to chemically complex alloy systems. We are focused on the unique multicomponent superlattice microstructures, nanoscale grain-boundary segregation, and disordering, as well as the various extraordinary mechanical and functional properties of these newly developed CCIMAs. Finally, perspectives on the future research orientation, challenges, and opportunities of this new frontier are provided.     

Mechanical,acoustic and electrical properties of porous Ti-based metallic glassy/nanocrystalline composites

The porous Ti-based metallic glassy/nanocrystalline composites were synthesized using powder metallurgy route. The sintered samples with different porosities can be obtained at sintering temperatures below glass transition temperature. The properties of the samples directly depend on the porosities and the sintered porous samples combine mechanical and acoustic properties of the porous crystalline material and the metallic glass, e.g. high strength, strong wave and energy absorption ability. Furthermore, the fundamental electrical behavior for this kind of novel porous material was also studied based on the percolation theory model, which helps to design and fabricate porous composites with unique electrical property. Our results suggest that the sintered porous composites have potentials for structural and functional applications.     

铝基非晶合金的研究进展

Al基非晶合金及纳米Al基非晶合金材料发展十分迅速,具有广阔的应用前景。综述了Al基非晶合金的制备、形成机制、玻璃形成能力、过热熔体脆性和块体Al基非晶合金及纳米Al基非晶复合材料的制备与性能等热点问题。     

Modulating the Mechanical Performance of Macroscale Fibers through Shear‐Induced Alignment and Assembly of Protein Nanofibrils

Protein‐based fibers are used by nature as high‐performance materials in a wide range of applications, including providing structural support, creating thermal insulation, and generating underwater adhesives. Such fibers are commonly generated through a hierarchical self‐assembly process, where the molecular building blocks are geometrically confined and aligned along the fiber axis to provide a high level of structural robustness. Here, this approach is mimicked by using a microfluidic spinning method to enable precise control over multiscale order during the assembly process of nanoscale protein nanofibrils into micro‐ and macroscale fibers. By varying the flow rates on chip, the degree of nanofibril alignment can be tuned, leading to an orientation index comparable to that of native silk. It is found that the Young's modulus of the resulting fibers increases with an increasing level of nanoscale alignment of the building blocks, suggesting that the mechanical properties of macroscopic fibers can be controlled through varying the level of ordering of the nanoscale building blocks. Capitalizing on strategies evolved by nature, the fabrication method allows for the controlled formation of macroscopic fibers and offers the potential to be applied for the generation of further novel bioinspired materials.