块体非晶合金Gd_（36）La_（20）Al_（24）Co_（20）晶化行为的研究

为深入理解非晶合金的晶化行为,有效控制合金的微观结构和性能,本文利用铜模铸造法制备了Gd36La20Al24Co20块体非晶合金,通过X射线衍射和差示扫描量热法对该非晶合金的热稳定性和晶化行为进行了研究.结果表明：Gd36La20Al24Co20块体非晶合金的晶化激活能为282.5 kJ/mol;与轻稀土基非晶合金相比...     

铝基非晶合金的制备、性能与应用研究进展

铝基非晶合金因其独特的物理和化学性能在诸多领域具有广泛的应用前景,综述了铝基非晶合金的成分体系、制备方法、性能特点及应用研究进展。首先,介绍了铝基非晶合金的发展历史和成分体系,目前铝基非晶主要分为3大体系：二元、三元和多元体系,以及综合性能和形成能力2大方面,多元体系表现更佳,并逐渐向更多元化发展;其次,系统介绍了铝基非晶合金的制备方法,包括粉末状、薄带状、块体样品的制备,相较于非晶薄带的制备,块体和粉状的制备方法较为丰富,而粉状非晶通常作为铝基非晶涂层的预制材料;随后,详细介绍了铝基非晶合金的性能特点、应用现状及发展趋势,从性能上来看,铝基非晶在强度和硬度以及耐腐蚀性能上表现良好,目前主要以涂层的形式参与应用,除此之外,研究者们也开始对磁性和热塑性展开研究,由于玻璃形成能力的限制,作为结构材料的应用较少;最后,对其未来应用前景进行了展望,认为涂层是目前铝基非晶合金最具应用前景的工程化方式。     

非晶合金零件成形技术研究进展

非晶合金作为一种结构不同于传统晶体金属、性能优异的新型材料一直是凝聚态物理学家和材料学家关注的热门领域。近几十年来,非晶合金的基础理论研究和制备工艺都取得了巨大进步,非晶合金作为一种极具应用前景的结构材料和功能材料,正在逐渐由实验室走向商业应用,推动科技发展。一种新材料想要最终走向商业应用,必须要有与之相适应的高生产率、低成本的零件成形技术。但是非晶合金的制备需要较快的冷却速率、高真空、高纯原料等苛刻条件,成本相对较高。同时非晶合金在室温下强度高、脆性大的特性使其难以机加工,热塑性成形时又极易发生晶化,难以成形大尺寸、复杂形状的零件,这严重限制了它的广泛应用。针对非晶合金的特点开发相应的零件成形技术成为学者们研究的重要课题。随着非晶成形能力较强的合金体系的出现,相应的非晶零件成形技术也得到了极大的发展。目前非晶合金的零件成形技术主要包括铸造成形、热塑性成形、焊接、粉末烧结、增材制造技术等,成形零件的尺寸极限跨及纳米至厘米尺度,复杂程度、制备和成形效率都得到大幅提升。但是每种成形技术都在成形效率、尺寸、性能、成本等方面有些许局限性,难以完全实现非晶合金零件的工业化生产和应用。本文简要综述了目前非晶合金铸造成形、热塑性成形、焊接、粉末烧结、增材制造技术的最新研究进展,分析了现有成形技术的优缺点及非晶合金成形的难点,最后指出外加能场复合、多种工艺复合的复合制造方式将是非晶合金零件成形技术未来发展的重要方向。     

非晶态合金焊接的研究进展

综述了近几年国内外非晶态合金在焊接方面的研究进展,简要分析了将大块非晶合金焊接成功的原因.目前可以成功焊接大块非晶合金的方法有:高压压实法、摩擦焊、闪光电阻焊、电子束焊、爆炸焊、激光焊.其中前两种焊接属于固相焊接,成功的原因主要是:块体非晶合金过冷液相区的热稳定性和超塑性.而其他几种属于液相焊接,成功的原因主要是:(1)非晶合金具有大的非晶形成能力;(2)焊接的能量高且集中,因而加热和冷却速度快于这些合金的临界冷却速度.大块非晶合金的焊接成功地推动了大块非晶合金在工程材料方面的应用.     

镁基大块非晶合金的研究进展

综述了镁基大块非晶合金的研究现状,重点介绍了微量元素、纳米颗粒对Mg-Cu-Y大块非晶的影响,并对现有非晶形成能力的判据进行了分析.对镁基非晶合金及其非晶复合材料的进一步研究提出了建议.     

非晶合金热塑性微成型技术研究概况及发展趋势

由于非晶合金的无定形结构,非晶合金在室温下表现出高强度、高硬度、加工性能差等特征。但是,非晶合金在过冷液相区内展现出低粘滞系数、高流动性能的超塑性特征,这为非晶合金的塑性加工提供了一种新的途径。论述了非晶合金过冷液相区热塑性微成型技术的特点,对比传统晶态材料总结了非晶合金作为理想微成型材料的优势。介绍了非晶合金在微机电系统(MEMS)产业领域诱人的应用前景,并列举了国内外相关专家学者在非晶合金热塑性微成型领域的研究成果。总结了非晶合金在微电子系统、精密光栅、微纳超疏水表面、生物芯片、微型燃料电池等领域的应用。同时,指明了非晶合金热塑性微成型技术发展过程中存在的问题,重申了开发非晶合金热塑性微成型技术的重要性。     

Fe基非晶合金粉末的研究进展

非晶合金粉末是指快冷雾化合金液滴所制得的合金粉末,其中Fe基非晶合金粉末因具有生产成本低廉和应用前景广阔等优势,一直备受青睐。同时,Fe基非晶合金粉末的应用也为块体Fe基非晶合金应用难的问题提供了一条崭新的途径。本文综述了Fe基非晶合金粉末的研究进展,对其在涂层制备、磁性材料、激光3D打印、废水处理4个方面的研究现状进行了归纳分类与总结,并分析了Fe基非晶合金粉末在各领域的应用优势。最后指出Fe基非晶合金粉末在制备高质量涂层、老化磁性粉末再利用及增材制造领域的研究方向,并展望了作为传感、控制等功能性器件的应用前景。此外,在薄膜等小尺寸、低维材料及柔性电子领域也展现出巨大的应用潜力。     

铝基非晶合金防腐蚀耐磨损性能的研究进展

Al基非晶合金具有优异的防腐蚀耐磨损性能.综述了Al基非晶合金由热处理和变形处理引起的晶化,介绍了Al基非晶合金材料防腐蚀耐磨损性能的研究现状,指出Al基非晶合金在控制非晶纳米晶比例、提高该非晶纳米晶涂层中非晶含量的研究动态,展望了Al基非晶合金材料在海洋装备防护等领域的运用价值.     

Cu基块体非晶合金的研究进展

综述了国内外最近几年来Cu基大块非晶合金的研究现状,介绍了Cu基大块非晶合金在玻璃形成能力、机械性能、耐腐蚀性能、非晶-纳米晶合金方面的研究成果,最后探讨了Cu基大块非晶合金未来的研究重点.     

高强度Cu基块状非晶合金的最新研究进展

Cu基块状非晶合金是一种新型高性能材料,从合金体系、力学性能、合金过冷液体区域的性能及非晶形成能力几方面对Cu基块状非晶合金的最新研究进展进行了综述,并展望了新型Cu基块状非晶合金的工程应用前景.     

Friction Stir Welding of Zr_(55)Al_(10)Ni_5Cu_(30) Bulk Metallic Glass to Crystalline Aluminum

The Zr55Al10Ni5Cu30 bulk metallic glass plate were successfully welded to crystalline aluminum plates by using a friction stir welding (FSW) method. The welded zone was examined. No defects, cracks or pores were observed and no other crystalline phases except for aluminum were found in the welded joint. The strength of the joint is higher than that of aluminum. The glassy phase in the stir zone keeps the amorphous state, showing a successful welding. The storage modulus softens over the glass transition. An...     

Low-field magnetic properties of wide Fe-Ni metallic glass strips

Wide samples of continuous-cast metallic glass ribbons fabricated to tape-wound or punched-ring core configurations are shown to possess the same attractive low-field magnetic properties as are observed in narrow ribbons of similar composition. Annealing ring-laminated cores in crossed fields leads to lower core loss than for metallic glass (wide or narrow) annealed only in a circumferential field.     

Micro flash butt welding of super duplex stainless steel with Zr-based metallic glass insert

Micro flash butt welding of super duplex stainless steel with Zr-based metallic glass insert was carried out. Zr₅₅Cu₃₀Ni₅Al₁₀ of Zr-based metallic glass with thickness of 50 μm and Zr metal with thickness of 500 μm were used as the insert materials. After welding, Zr-based metallic glass insert became much thinner than that of Zr metal insert. The supercooled liquid of Zr-based metallic glass insert at the interface was protruded outside of the specimen during welding. The formation of the protrusion discharged the oxide films on the butting surfaces and contact surface, resulting in metallurgical bonding through the fresh surfaces. The Fe-Zr metallic compounds were observed at the bonding interface for the Zr metal insert, but the metallic compound for Zr-based metallic glass insert was hardly observed. The micro flash butt welding of stainless steel with Zr-based metallic glass insert was successfully welded.     

超声波筛选激光增材制造非晶合金

目的 快速优化出无缺陷非晶合金激光增材制造工艺。方法 以Zr51Ti5Cu25Ni10Al9非晶合金为模型材料,利用超声波对金属内部缺陷的衰减,来快速筛选激光增材制造非晶合金的最佳工艺组合（激光功率和扫描速度）。结果 超声波检测可以准确有效地检测出非晶合金试件的晶化比例,并且当激光功率为1 300 W、扫描速度为600 mm/min时超声波衰减系数降至最低。进一步对该工艺下获得的样品分析发现,该工艺成型的Zr51Ti5Cu25Ni10Al9非晶合金缺陷最少、晶化程度最低、性能最佳。结论 超声波技术是快速筛选激光增材制造非晶合金等高性能金属最佳工艺参数的有效技术手段。     

Cold welding behavior of metallic glass nanowires: Insights from large-scale numerical simulations

Cold welding technique at room temperature is the preferred option in nano-assembly and nano-jointing. In this study, the cold welding behavior and mechanical strength of Cu₅₀Zr₅₀ metallic glass nanowires (MGNWs) in head-to-head contact are investigated by molecular dynamics simulation based on the embedded atom method potential. Effects of welding velocity, operating temperature, and size of nanowires are discussed with the consideration of stress, shear strain, atomic deformation processes, and weld quality. Our simulation results demonstrate that a desirable weld quality can be obtained at room temperature. With an increase in welding velocity, the shear deformation zones of the welded MGNWs increase, leading to a decrease in mechanical strength. However, the effect of temperature on the weld quality is not pronounced. Besides, the elongation ability of the welded MGNWs increases with increasing diameters of nanowires. Smaller diameter results in better weld quality due to the size effect of metallic glass. For a pair of MGNWs with different diameters, the necking and fracture of the welded MGNWs occur in the regions of the nanowire with a relatively smaller diameter. This study carries major implications for the fabrication and structural assembly of metallic glass-based nanomaterials.

Graphical Abstract

     

Optimisation of a GMT-based cold pressing technique for low cost textile reinforced thermoplastic composites

Much potential and interest exists for the fast processing of lightweight, inexpensive composite preforms in automotive and other transport applications. As a thermoplastic matrix is more suitable for mass production with short cycle times, a novel cost-effective glass fibre reinforced thermoplastic textile preform is developed. Weft-inserted warp knitting is used to produce this textile preform containing both the reinforcing fibres and the thermoplastic matrix material as split-film ribbons. The aim of the work is to establish a useful processing technique and to control those parameters which lead to the production of good quality composite parts. The current study is specifically directed at determining the feasibility of the GMT-based cold pressing technique for the manufacturing of this new type of thermoplastic composite. An experimental design method is used to develop a statistical model which gives response surfaces of the effects of the processing parameters on the mechanical performance of the final composite part. Processing variables are ranked in order of importance to determine the optimal processing window. An economical comparison with the use of long fibre reinforced GMT mats proves the cost-efficiency of this new continuous reinforced thermoplastic composite.     

Facile fabrication of ultrathin freestanding nanoporous Cu and Cu-Ag films with high SERS sensitivity by dealloying Mg-Cu(Ag)-Gd metallic glasses

Nanoporous metals prepared by dealloying have attracted increasing attention due to their interesting size-dependent physical,chemical,and biological properties.However,facile fabrication of metallic ultra-thin freestanding nanoporous films(UF-NPFs)by dealloying is still challenging.Herein,we report a novel strategy of facile preparation of flexible Cu,Cu3Ag,and CuAg UF-NPFs by dealloying thick Mg-Cu(Ag)-Gd metallic glass ribbons.During dealloying,the local reaction latent heat-induced glass transition of the precursor ribbons leads to the formation of a solid/liquid interface between the initially dealloyed nanoporous layer and the underlying supercooled liquid layer.Due to the bulging effect of in situ gen-erated H2 on the solid/liquid interface,Cu,Cu3Ag,and CuAg UF-NPFs with thicknesses of～200 nm can self-peel off from the outer surface of the dealloying ribbons.Moreover,it was found that the surface-enhanced Raman scattering(SERS)detection limit of Rhodamine 6G(R6G)on the Cu and CuAg UF-NPF substrates are 10-6 M and 10-11 M,respectively,which are lower than most of the Cu and Cu-Ag sub-strates prepared by other methods.This work presents a reliable simple strategy to synthesize a variety of cost effective and flexible metallic UF-NPFs for functional applications.     

An inverse analysis method to estimate inherent deformations in thin plate welded joints

Weld-induced distortion occurs as an unavoidable consequence due to the intrinsic nature of non-uniform heating and fast cooling. Welding distortion not only negatively affects manufacturing accuracy, but also increases fabrication cost due to straightening work. Past researches suggest that elastic finite element method based on inherent strain theory is an effective approach to estimate welding deformation for welded structures. However, when this method is used to simulate welding deformation in a large or complex structure, the values of inherent deformations in each typical joint must be known beforehand. In the present study, a new method based on inverse analysis was developed to obtain the inherent deformations in typical welded joints. Meanwhile, the influence of weld length on welding deformation was investigated. In addition, using the proposed method, a database of inherent deformations in thin plate butt joints was established.     

Strength development versus process data in ultrasonic welding of thermoplastic composites with flat energy directors and its application to the definition of optimum processing parameters

Ultrasonic welding of thermoplastic composites is a very interesting joining technique as a result of good quality joints, very short welding times and the fact that no foreign material, e.g. a metal mesh, is required at the welding interface in any case. This paper describes one further advantage, the ability to relate weld strength to the welding process data, namely dissipated power and displacement of the sonotrode, in ultrasonic welding of thermoplastic composite parts with flat energy directors. This relationship, combined with displacement-controlled welding, allows for fast definition of optimum welding parameters which consistently result in high-strength welded joints.     

Preparation of metallic glass powders by hydrogen charging

Metallic glass powders were produced by exposing metallic glass alloy ribbons to hydrogen at pressures of 12–15 MPa. A list of powders prepared by this method was given. Some metallic glass powders, such as CuTi, were difficult to remove hydrogen for them, indicating strongly bound hydrogen in them.