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.

Cast bulk glassy alloys:fabrication,alloy development and properties

Metallic glasses represent an interesting group of materials as they possess outstanding physical, chemical and mechanical properties compared to their crystalline counterparts.Currently, with well designed compositions it is possible to cast liquid alloys into the glassy state at low critical cooling rates from 100 K·s-1 to 1 K·s-1 and in large critical sample sizes up to several centimeters, which significantly enhances the promise for possible applications as advanced engineering materials.This paper reviews the development of (ZrCu)-based bulk metallic glasses with large sizes by copper mold casting and their unique properties.Additionally, the ex-situ and in-situ second phases reinforced BMG composites with large plasticity are also presented.

Synthesis,structure and mechanical properties of Zr-Cu-based bulk metallic glass composites

The unusual glass-forming ability（GFA） of the Zr48Cu36Ag8Al8 alloy and the high ductility of the Zr48Cu36Ag8Al8 metallic glass-matrix composites containing Ta powder were reported.The bulk metallic glass rod with a diameter of 25 mm was successfully synthesized using copper mold casting for the Zr48Cu36Ag8Al8 alloy.High GFA of this alloy was found to be related to a large supercooled liquid region and a quaternary eutectic point with low melting temperature.The bulk metallic glass matrix composites were prepared by introducing extra Ta particles into the Zr48Cu36Ag8Al8 melt.The composites consist of Ta particles homogenously distributed in the Zr48Cu36Ag8Al8 metallic glass matrix.The optimum content of Ta powder is 10at%for the composite with the highest plasticity,which shows a plastic strain of 31%.

Synthesis,properties and XPS analysis of Cu-,Ni-,Ti-based metallic glasses

Metallic glasses(MG)represent an interesting group of materials as they possess outstanding physical,chemical and mechanical properties compared to their crystalline counterparts.This paper reviews the synergistic influence of Ni and Nb elements on thermal stability of supercooled liquid and corrosion resistance of as-cast Cu-Zr(Hf)-Ti-Ni-Nb bulk metallic glasses(BMGs).Additionally,in-situ second phase reinforced Cu-based BMG composites with high corrosion resistance and excellent mechanical properties are investigated.On the other hand,this paper reports the development of ultra-high corrosion resistant Ni-based metallic glasses at high temperatures for their potential applications.Corrosion resistance and XPS analysis of the Nifree Ti-based BMG are also introduced.

块状铁基非晶态合金的软磁性能

1.前言 至今已经发现了若干非晶态合金系列,如Ln-Al-TM,Mg-Ln-TM,Zr-Al-TM,Ti-Zr-TM,Ti-Zr-Be-TM等(Ln代表镧系金属,TM代表过渡族金属),在晶化前有宽的、超过100K的过冷液态温度范围ΔT_x(ΔT_x=晶化温度T_x-玻璃转变温度T_g)。

具有高玻璃形成能力、高强度和优良软磁性能的块状Fe-Mo-Ga-P-C-B玻璃合金

1.前言 最近三十年,人们一直期盼铁基玻璃合金能具有一种综合性能,即高的玻璃形成能力、晶化前有大的过冷液态范围、高的机械强度和优良的磁性能。但是,直到八十年代末期。

新的具有宽过冷液态区域和优良软磁性能的Fe-Co-Ni-Zr-B非晶态合金

1.前言 大家知道,用急冷淬火技术制备的非晶态合金薄带具备很有用的机械性能、物理性能和化学性能,这是因为它们的原子组态是无序的、没有晶粒边界和奇异的合金成分。这些性能中,软磁性能特别重要。

Highly efficient nanoporous CoBP electrocatalyst for hydrogen evolution reaction

Water splitting is an environment friendly and efficient way to produce hydrogen.Highly efficient and low-cost non-noble metal catalysts play an important role in hydrogen evolution reaction(HER).Dealloying is a simple method to prepare three-dimensional self-supporting nanoporous materials without conductive supports and binders.In this work,we prepared self-supporting nanoporous CoBP electrocatalyst by dealloying method.The influence of the synergistic effect of nonmetallic elements on catalytic activity was investigated.The synergistic electronic effect of Co,B and P atoms on the surface optimizes the H atoms desorption and results in superior HER activity.The bi-continuous structure of nanoporous CoBP provides more active area and favors of electron and electrolyte transfer.The nanoporous CoBP with the B/P atomic ratio of 1/3 exhibits low overpotential of 42 mV at 10 mA·cm^(-2),small Tafel slope of 39.8 mV·dec-1 and good long-term stability with no performance decrease for 20 h in alkaline solution.

Structural homology of the strength for metallic glasses

The structure-property relationship,one of the central themes in materials science,is far from being well understood for metallic glasses(MGs)due to the great complexity of their amorphous structures.Based on the analysis of published experimental data for 165 MGs from more than 15 different alloy systems,the present study reveals a universal dependence of mechanical properties(Young’s moduli,shear moduli and yield strength)on simple structural parameters(the inter-atomic distance and/or valence electron density)originating from the interatomic potential and Fermi sphere-Brillouin zone interaction.This work establishes a structure-property relationship for metallic glasses and provides insights into the fundamentals of the mechanical properties of disordered systems.

Understanding the macroscopical flexibility/fragility of nanoporous Ag:Depending on network connectivity and micro-defects

The effective engineering applications of nanoporous metals(NPMs)in flexible energy storage and wearable healthcare biosensor monitoring require its uniform ligaments network,specifically crack-free and flexible monolithic bodies.However,the macroscopic fragility of NPMs restricts their applications in wearable electronics fields.Here we focus on the synthetization of highly flexible NPMs.The effects of structural factors,e.g.ligament-network connectivity and micro-cracks on the mechanical properties of nanoporous Ag(np Ag)are investigated.The well-interconnected np Ag metal exhibits higher tensile strength,nanohardness and Vickers hardness than those for the ill-interconnected np Ag metal.The quality of the network connectivity dominates the strength and hardness of the np Ag.The flexibility/fragility is determined by the micro-crack in np Ag.The crack-free np Ag exhibits good flexible behavior.When micro-cracks are introduced,the np Ag becomes fragile.The control of soft volume shrinkage rate(Vsr)and slow surface diffusivity(Ds)effectively suppresses the crack initiation and propagation of as-formed np Ag.These results provide useful insights to synthesize more flexible and crack-free NPM materials for effective use in public wearable electronics and diverse flexible engineering applications in the future.

Microstructure and mechanical properties of TC4 joints brazed with Ti-Zr-Cu-Sn amorphous filler alloy

The Ti_(51.44)Zr_(16.26)Cu_(30)Sn_(2.3)(at%)amorphous filler alloy in a ribbon form was prepared by melt spinning.The Ti-6 Al-4 V alloy was brazed in vacuum furnace by using the Ti_(51.44)Zr_(16.26)Cu_(30)Sn_(2.3)amorphous filler alloy.The effects of brazing temperature and holding time on the interfacial microstructure and mechanical properties of the Ti-6 Al-4 V brazed joints were investigated.The brazed joints are composed ofα-Ti,β-Ti,and(Ti,Zr)_(2)Cu phases.The shear strength of the joints increases with brazing temperature increasing from 1153 to 1193 K and holding time from 10 to 15 min,while decreases with brazing temperature and time further increasing.Low temperature brazing results in the formation of microcracks and voids in the seams,which are harmful for the shear strength of the joints.In the joint brazed at 1193 K for 15 min,a fineα+βWidmansta¨tten structure beneficial to the mechanical property is formed,and the joint exhibits relatively high joint strength of 180 MPa.

Zr_(55)Al_(10)Ni_(5)Cu_(30)amorphous alloy film prepared by magnetron sputtering method

In this work,amorphous Zr_(55)Al_(10)Ni_(5)Cu_(30)alloy thin film was prepared on D36 steel substrate by magnetron sputtering method.The film was characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),atomic force microscopy(AFM),hardness tester and nano indentation.Corrosion behavior of the film was investigated in 3.5%NaCl aqueous solutions by an electrochemical method.At room temperature,the amorphous alloy film was formed completely after sputtering for 5 h.The surface morphology of the amorphous alloy film was uniform and smooth.Formation of the amorphous alloy film improved the microhardness and corrosion resistance of the D36 substrate.The amorphous alloy film(prepared at room temperature for 5 h)exhibited good adhesion strength with the substrate.The as-sputtered sample exhibited a crevice corrosion trend when the sputtering time was too short(1 h)or too long(10 h).