Metallic glass ribbon-reinforced glass-ceramic matrix composites

The role of metallic glass ribbons in modifying the properties of glass-ceramics was investigated using specimens prepared by conventional pressing and sintering techniques. Even very low volume fractions of such reinforcements were found to provide significant improvements in the strength, elastic properties and fracture toughness of the glass-ceramic matrices. The observed improvement in the fracture toughness is explained on the basis of various metallic glass ribbon-related energy absorbing mechanisms.     

Permeability of glass ribbon-reinforced composites

An analytical model of the fluid permeability of glass ribbon-reinforced organic matrix composites is presented. The analysis indicates that such composites, with ribbon aspect ratios in the range 50 to 200 offer 100 to 1000 fold improvement in permeation resistance over fibre glass composites. This is pertinent to the application of composites for storage containers, pressure vessels, and pipelines. Permeation characteristics of glass ribbon composites were determined experimentally through mass spectrographic measurements of helium penetration. These measurements qualitatively supported the analytical model.     

Microstructure and mechanical properties of aluminum alloy matrix composites reinforced with Fe-based metallic glass particles

Fe-based metallic glass (FMG) particles reinforced Al-2024 matrix composites were fabricated by using the powder metallurgy method successfully. Mechanical alloying result in nanostructured Al-2024 matrix with a grain size of about 30 nm together with a good distribution of the FMG particles in the Al matrix. The consolidation of the composites was performed at a temperature in the super-cooled liquid region of the FMG particles, where the FMG particles act as a soft liquid-like binder, resulting in composites with low or zero porosity. The microstructure and mechanical properties of the composites were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and compression test. The yield and fracture strength of the composites are 403 MPa and 660 MPa, respectively, while retaining a considerable fracture deformation of about 12%. The strengthening mechanism is associated with the grain refinement of the matrix and uniform distribution of the FMG particles.     

Shear band formation and mechanical properties of cold-rolled bulk metallic glass and metallic glass matrix composite

The effects of cold rolling on the mechanical properties of monolithic Vitreloy 1 (Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5) BMG and ductile phase reinforced in-situ composite (Zr_56.3Ti_13.8Cu_6.9Ni_5.6Nb_5.0Be_12.5) have been investigated. The bend strength of the as-cast composite was lower than that of the as-cast monolithic BMG. However, the bend deflection of the as-cast composite (1.0 mm) was significantly higher than that of the as-cast monolithic BMG. The ductility of the monolithic BMGs is improved by cold rolling. In contrast, the ductility of the metallic glass matrix composite is deteriorated after cold rolling.     

金属玻璃基复合材料的微结构效应

基于自由体积理论和Ramberg-Osgood模型,并利用ABAQUS软件,建立颗粒随机分布代表性体积单元模型,模拟了Ti_(64.5)Zr_(14.5)V_(18.5)Cu_(2.5)颗粒增韧Ti基金属玻璃基复合材料在单轴拉伸状态下的微结构效应,讨论了颗粒的体积分数、团聚数目、长径比、定位取向和界面对金属玻璃韧性的影响。结果表明:提高颗粒体积分数能显著提高复合材料的塑性,但部分牺牲了复合材料的强度;增大颗粒长径比能够增强复合材料的塑性和屈服强度;使颗粒的取向与荷载方向成90°或0°,不仅增强了复合材料的塑性,而且与其他排布相比也增强了复合材料的强度;减少团聚数目至2个以下,能明显减少金属玻璃基复合材料的塑性和强度的损失,使团聚中颗粒与荷载成90°,却能改善复合材料的塑性和强度;在颗粒增韧金属玻璃基复合材料中加入零厚度界面,能观察到在主剪切带上颗粒和基体在界面处脱粘,得到与实验现象更加吻合的结果。通过上述的研究能够很好地理解复合材料的微结构效应,并有利于材料的设计。     

Production and mechanical properties of metallic glass-reinforced Al-based metal matrix composites

Al-based metal matrix composites were synthesized through powder metallurgy methods by hot extrusion of elemental Al powder blended with different amounts of metallic glass reinforcements. The glass reinforcement was produced by controlled milling of melt-spun Al₈₅Y₈Ni₅Co₂ glassy ribbons. The composite powders were consolidated into highly dense bulk specimens at temperatures within the supercooled liquid region. The mechanical properties of pure Al are improved by the addition of the glass reinforcements. The maximum stress increases from 155 MPa for pure Al to 255 and 295 MPa for the samples with 30 and 50 vol.% of glassy phase, respectively. The composites display appreciable ductility with a strain at maximum stress ranging between 7% and 10%. The mechanical properties of the glass-reinforced composites can be modeled by using the iso-stress Reuss model, which allows the prediction of the mechanical properties of a composite from the volume-weighted averages of the components properties.     

Microstructure and mechanical properties of barium aluminosilicate glass-ceramic matrix composites reinforced with SiC whiskers

BAS glass-ceramic composites reinforced with different volume fractions (0, 10, 20, 30, 40 vol%) of SiC whiskers were successfully fabricated by a hot-pressing method. The microstructure, whisker/matrix interface structure, phase constitution and mechanical properties of the composites have been systematically studied by means of SEM, TEM, XRD techniques as well as three-point bending tests. It was demonstrated that the incorporation of SiC whiskers could significantly increase the flexural strength and fracture toughness of BAS glass-ceramic matrixes. The celsian seeds can effectively promote the hexacelsian-to-celsian transformation in BaAl₂Si₂O₈. The active Al₂O₃ added to the BAS matrix obviously reduced the amount of SiO₂ in the matrix and formed needle-like mullite. The high temperature strengths of the composites were also investigated.     

Fabrication and mechanical characterization of a series of plastic Zr-based bulk metallic glass matrix composites

Coupling the high yielding strength with enhanced plasticity under compression at ambient temperature, a series of Zr-based bulk metallic glass matrix composites are designed based on a pseudo ternary phase diagram. The largest compressive fracture plastic strain of 17.0% with the yielding strength of 1070 MPa is available for Zr_60.0Ti_14.7Nb_5.3Cu_5.6Ni_4.4Be_10.0 bulk metallic glass matrix composite. The relationship between the cooling rate and the microstructure, the microstructure and the mechanical properties, and the fractographs of the composites is carefully identified.     

连续长玻璃纤维/聚氨酯复合材料的制备与力学性能

以三羟基聚醚多元醇（PPG）、二苯基甲烷二异氰酸酯（MDI）作为软段和硬段,玻璃纤维（GF）为增强体,采用预聚体法制备自交联型GF/聚氨酯（PU）复合材料。借助旋转式黏度计、DMA、SEM、XRD和万能力学试验机等分析检测手段,研究了PU预聚体聚合温度、适用期、物相及GF含量等因素对GF/PU复合材料力学性能的影响。结果表明:PU预聚体聚合温度为50℃,GF含量为55wt%时,GF/PU复合材料综合性能最优,拉伸强度、弯曲强度和冲击韧性分别为794 MPa、846 MPa和228 kJ/m2,动态力学性能损耗因子（tanδ）峰值为0.59。      

Csf/BAS玻璃陶瓷复合材料的制备及其力学性能研究

为了提高钡长石(BAS)玻璃陶瓷的力学性能,采用轧膜成型、热压烧结方法制备出纤维分布均匀的致密短碳纤维增强BAS玻璃陶瓷基复合材料(Csf/BAS).采用X射线衍射分析,扫描电子显微镜、透射电子显微镜观察及三点弯曲法与单边开口梁法研究了纤维含量对复合材料组织及力学性能的影响.研究表明:Csf对BAS玻璃陶瓷有良好的强韧化效应.体积分数为30%Csf/BAS复合材料的室温抗弯强度及断裂韧性分别为255 MPa和3.45 MPa.m1/2,其主要的韧化机制为裂纹偏转、纤维的拔出与桥接.用摩尔分数25%Sr代替Ba实现了基体的六方→单斜相的完全转变,进一步提高了复合材料的力学性能.     

Improved elevated temperature mechanical properties of graphene-reinforced pure aluminium matrix composites

ABSTRACT

In this study, graphene nanoplatelets (0.25 and 0.5?wt-%) reinforced aluminium matrix composites were synthesised. Microstructures of composites were investigated by X-ray diffraction, scanning electron microscope and transmission electron microscope. Hardness was measured according to the Vickers test method. Tensile tests were performed at both room (25°C) and elevated temperatures (150°C and 250°C). Results showed that hardness was improved with direct addition of graphene. Microstructure of composites was free of macro defects. Yield and tensile strength behaviours of pure aluminium were increased with the addition of graphene especially at room temperature. Graphene-reinforced samples have higher compressive residual stress. From the outer surface to inner surface, transition from compressive to tensile residual stress was observed for samples.     

Effect of ECAP consolidation temperature on the microstructure and mechanical properties of Al-Cu-Ti metallic glass reinforced aluminum matrix composite

Al_(65)Cu_(20)Ti_(15)metallic glass(AMG) reinforced Al matrix composites were consolidated by equal channel angular pressing(ECAP) process. The effects of ECAP consolidation temperature ranging from room temperature to just below the first crystallization temperature of metallic glass on the consolidation of composites were investigated in terms of the relative densities, structural evolutions and mechanical properties of composites. Some intermetallic compounds included Al_5CuTi_2, Al_3Ti and Al_4Cu_9 precipitated from metallic glass particles at consolidation temperature of 300?C. Consolidation temperature did not affect the matrix grains size of the composite. Quantitative analysis revealed that the distribution of reinforcing particles was considerably dependent on consolidation temperature. Density of the composite was increased by increasing the consolidation temperature to 250?C. The composite consolidated at250?C through ECAP process, exhibited the best combination of yield strength and ductility of 184 MPa and 48%, respectively.     

塑性钛基非晶复合材料的制备及性能

通过铜模喷铸法成功制备了一系列内生β-Ti(Zr, Nb)枝晶增塑的Ti-Zr-Nb-Cu-Be非晶复合材料, 研究了成分对枝晶体积分数及尺寸的影响及其对复合材料力学性能的调节作用。结果表明, Ti₄₈Zr₂₀Nb₁₂Cu₅Be₁₅合金压缩强度达到2061 MPa, 塑性变形高达22.5%, 表现出优异的综合力学性能。 非晶复合材料的塑性不仅与β-Ti(Zr,Nb)枝晶相的体积分数有关, 而且受到枝晶尺寸的强烈影响, 在一定体积分数条件下, 枝晶相的尺寸越大, 对剪切带的阻碍作用越明显, 合金的塑性越高。     

内生非晶复合材料组织与力学性能调控研究进展

非晶合金因其独特的短程有序、长程无序原子结构特征, 使其具有了一系列优异的力学、物理、化学等性能, 在先进金属结构材料领域具有巨大的潜在应用价值。但非晶合金在室温承载变形时, 原子团簇发生剪切转变形成的大量自由体积会演化为高度局域化剪切带, 局域化剪切带由于缺乏介质的阻碍会发生失稳扩展, 导致非晶合金极易发生室温脆断, 特别单轴拉伸时基本无塑性。为克服这个缺憾, 研究者们提出将微米级尺寸的晶体相引入非晶来抑制剪切带的失稳扩展, 使得内生第二相增韧非晶复合材料具有了明显的拉伸塑性能力, 因此倍受材料学界的关注。近年来, 研究者们陆续通过成分设计、制备技术、热处理工艺等方法来实现非晶复合材料的塑性变形能力的提升, 使得非晶复合材料有望走向实际的工程应用。本文围绕内生第二相增韧非晶复合材料的微观组织调控这一关键科学问题, 从影响非晶复合材料微观组织结构的因素(合金成分设计、制备工艺参数、微观结构构筑等)到微观组织对其室温力学性能的影响机制两方面的研究成果进行了系统总结, 重点阐述了近10年来内生第二相增韧非晶复合材料领域组织调控及其室温力学性能关联性方面的研究进展, 并且对内生非晶复合材料研究领域目前的存在的问题和挑战进行了展望, 以期为高强高韧内生第二相增韧非晶复合材料的设计与制备提供理论参考。     

Highly enhanced mechanical properties in Cu matrix composites reinforced with graphene decorated metallic nanoparticles

This study investigated the preparation and mechanical performance of graphene/metal composites using Ni nanoparticles decorated graphene nanoplatelets (Ni-GPLs) as a reinforcing component in Cu matrix (Ni-GPL/Cu). Ni-GPLs consisting of well-dispersed Ni nanoparticles strongly attached on GPLs were successfully synthesized by chemically reducing Ni ions on the surface of GPLs. The Ni-GPL/Cu composites with only 0.8 vol% Ni-GPLs exhibited a significant improvement in ultimate tensile strength (UTS), being 42 % higher than that of monolithic Cu. The significant strength enhancement is attributed to the unique structure of Ni-GPLs, which was expected to generate a good dispersion and strong GPL–Cu interfacial bonding. The UTS of 0.8 vol% GPL/Cu composites was even lower than that of the monolithic Cu due to the GPL aggregates. The obtained results indicated that Ni-GPLs are novel and effective reinforcing components for greatly improving the mechanical properties of the graphene/metal composites.     

CuZr-based bulk metallic glass and glass matrix composites fabricated by selective laser melting

Monolithic bulk metallic glass and glass matrix composites with a relative density above 98 ％ were produced by processing Cu46Zr46Al8 (at.％) via selective laser melting (SLM).Their microstructures and mechanical properties were systematically examined.B2 CuZr nanocrystals (30-100 nm in diameter) are uniformly dispersed in the glassy matrix when SLM is conducted at an intermediate energy input.These B2 CuZr nanocrystals nucleate the oxygen-stabilized big cube phase during a remelting step.The presence of these nanocrystals increases the structural heterogeneity as indirectly revealed by mircrohardness and nanoindentation measurements.The corresponding maps in combination with calorimetric data indicate that the glassy phase is altered by the processing conditions.Despite the formation of crystals and a high overall free volume content,all additively manufactured samples fail at lower stress than the as-cast glass and without any plastic strain.The inherent brittleness is attributed to the presence of relatively large pores and the increased oxygen content after selective laser melting.     

Characterization of mechanical properties of FeCrBSiMnNbY metallic glass coatings

This article investigates mechanical characteristics of Fe-based metallic glass coatings. A series of the coatings were fabricated by conventional wire-arc spray process. The microstructure of the coating was characterized by means of X-ray diffraction, scanning election microscopy equipped with energy dispersive X-ray analysis, transmission electron microscopy, and differential scanning calorimeter. The coating is very dense smooth, adhering well and with no cracking. The microstructure of the coating consists of amorphous phase and α(Fe,Cr) nanocrystalline phase. The nanocrystalline grains with a size of 30 to 60 nm are homogenously dispersed in the amorphous phase matrix. The crystallization temperature of the amorphous phase is about 545 °C. The mechanical properties, such as porosity, adhesive strength, microhardness, elastic modulus, and abrasive wear resistance, were analyzed in detail. The experimental results indicate that the coating has high microhardness (15.74 GPa), high elastic modulus (216.97 GPa), and low porosity (1.7%). The average adhesive strength value of the coating is 53.6 MPa. The relationship between abrasive wear behavior and structure of the coating is discussed. The relatively wear resistance of metallic glass coating is about 7 and 2.3 times higher than that of AISI 1045 steel and 3Cr13 martensite stainless steel coating, respectively. The main failure mechanism of metallic glass coating is brittle failure and fracture. The Fe-based metallic glass coating has excellent wear resistance.     

Elevated temperature sliding wear behavior of WCP-reinforced ferrous matrix composites

WC_P-reinforced ferrous matrix composites were processed by direct addition of WC_P (100–150 μm) and the melt of the matrix alloy to a rotating mold at 1000 rpm. Dry sliding wear behaviors of the composites containing about 80 vol.% of WC_P and high-speed steel counterpart were investigated at room temperature and 400 °C against a rotating die steel ring. And wear experiments were performed under loads of 50, 100, and 150 N and a fixed sliding velocity of 30 m/s. Results show that at room temperature, both materials exhibited a marked increase in wear rate with load applied. Wear rates of the composites and high-speed steel under loads of 50, 100, and 150 N at room temperature achieved 1.61 × 10⁻⁶, 2.14 × 10⁻⁶, 3.56 × 10⁻⁶, and 3.11 × 10⁻⁶, 23.08 × 10⁻⁶, 57.39 × 10⁻⁶ g/m, respectively. At a testing temperature of 400 °C, the composites exhibited a marked increase in wear rates and high-speed steel exhibited mild wear (characterized by extremely low wear rates) over the range of loads considered in these experiments. Wear rates of both the composites and high-speed steel at 400 °C achieved 2.42 × 10⁻⁶, 5.19 × 10⁻⁶, 6.64 × 10⁻⁶, and 4.1 × 10⁻⁶, 8.92 × 10⁻⁶, 26.02 × 10⁻⁶ g/m, respectively, under different loads. Finally, the wear-mechanism was discussed in this article.     

Plasticity improvement for dendrite/metallic glass matrix composites by pre-deformation

The mechanical properties of in-situ metallic glass matrix composites (MGMCs) are investigated by tensile pre-deformation, followed by compression. The pre-deformation is utilized to exploit notable increases in plasticity, accompanied by slight increases in the compressive strength, and the deformation mechanisms are explored. The increased free volumes in the glass matrix after tensile pre-deformation contribute to the decrease of the Young's modulus of the glass matrix and lead to the increase in the stress concentration, promoting multiplication of shear bands. When the Young's modulus of the glass matrix matches that of the dendrites, the plasticity of in-situ dendrite-reinforced MGMCs is the optimized. Matching Young's modulus opens a door to design the MGMCs with excellent plasticity and remarkable work-hardening capability.