3%无取向硅钢薄板的表面纳米化结构与性能

为了探索金属薄板表面纳米化制备方法,本工作选取3%无取向硅钢热轧板进行表面机械研磨处理（SMAT）和异步轧制（CSR）,研究深度方向结构和硬度的变化.结果表明：SMAT过程中,3%无取向硅钢通过位错的演变,在表面形成了等轴状、尺寸约为10 nm的、取向呈随机分布的纳米晶,纳米晶层厚度约为20μm;SMAT样品经过CSR后,表面的显微组织基本不变,但纳米晶层的厚度明显减小;SMAT和CSR处理使表面硬度显著提高（约为85%）.本工作表明,SMAT与CSR复合工艺可以制备大尺寸的、具有纳米结构表层的金属薄板.     

普及金属腐蚀与防护知识重要性的研究

从腐蚀的危害、常用的防腐蚀方法、人为造成的腐蚀破坏,以及普及腐蚀与防护知识等方面讨论了因腐蚀而造成的损失和防腐蚀的重要性,提出应大力普及金属腐蚀与防护的基本知识,减少腐蚀损失和腐蚀事故的发生.     

氰渣低温微熔锍化资源化技术

黄金行业产出的氰渣已列为固体危废,其脱毒处置技术是所有黄金企业不得不面对的严峻挑战和必须尽快解决的重大难题。探究了利用低温微熔锍化法处置低品位氰渣并高效回收贵金属及有价金属的技术可行性。考察了焙烧温度、焙烧时间及添加剂用量等条件对贵金属回收率的影响,阐明了在促进剂、低温和还原气氛作用下形成低熔点金银及铜铅锌等有价金属锍化物晶核长大再次矿化、骤冷后浮选回收的机理。在优化条件下处理含金1.71 g/t、银54 g/t、铁32.71%的氰化尾渣,渣中金品位可降至0.14 g/t,浮选精矿中金、银的品位分别达到35.46、737.14 g/t,金、银的平均回收率分别达到92.44%、80.67%,磁选所得铁精矿中铁的品位为63.57%,回收率83%,产率68%。有效回收贵金属的同时,实现了低品位氰渣的无害化处置和资源化利用。     

黑色金属常温磷化发黑

提出了一种新型黑色金属常温磷化发黑工艺，研究了影响膜层质量的各种因素，结果表明，常温磷化发黑集常温发黑和常温磷化二者的优点，磷化发黑膜层是磷化膜与发黑膜协同生长形成的“共生膜”。黑色金属在10－15℃范围内处理6－10min，可以获得防护和装饰性能优良的磷化发黑膜。     

Application of High-Speed Laser Polarimetry to Noncontact Detection of Phase Transformations in Metals and Alloys at High Temperatures

A high-speed laser polarimetry technique, developed recently for the measurement of normal spectral emissivity of materials at high temperatures, was used to detect solid–solid and solid–liquid phase transformations in metals and alloys in millisecond-resolution pulse-heating experiments. Experiments were performed where normal spectral emissivity at 633 nm was measured simultaneously with surface radiance temperature, resistance, and/or voltage drop across the specimen. It was observed that a phase transformation, as indicated either by an arrest in the specimen radiance temperature or changes in the resistance and/or voltage drop, generally caused a change in normal spectral emissivity. Experiments were conducted on cobalt, iron, hafnium, titanium, and zirconium to detect solid–solid phase transformations. Similar experiments were also performed on niobium, titanium, and the alloy 85titanium–15molybdenum (mass%) to detect solid–liquid phase transformations (melting).     

Microfluidic Mass Production of Stabilized and Stealthy Liquid Metal Nanoparticles

Functional nanoparticles comprised of liquid metals, such as eutectic gallium indium (EGaIn) and Galinstan, present exciting opportunities in the fields of flexible electronics, sensors, catalysts, and drug delivery systems. Methods used currently for producing liquid metal nanoparticles have significant disadvantages as they rely on both bulky and expensive high‐power sonication probe systems, and also generally require the use of small molecules bearing thiol groups to stabilize the nanoparticles. Herein, an innovative microfluidics‐enabled platform is described as an inexpensive, easily accessible method for the on‐chip mass production of EGaIn nanoparticles with tunable size distributions in an aqueous medium. A novel nanoparticle‐stabilization approach is reported using brushed polyethylene glycol chains with trithiocarbonate end‐groups negating the requirements for thiol additives while imparting a “stealth” surface layer. Furthermore, a surface modification of the nanoparticles is demonstrated using galvanic replacement and conjugation with antibodies. It is envisioned that the demonstrated microfluidic technique can be used as an economic and versatile platform for the rapid production of liquid metal‐based nanoparticles for a range of biomedical applications.     

纳米结构金属位错的研究进展

综述了国内外近年来对纳米结构金属位错的研究,包括位错的基本特征、研究方法以及定量分析.由于晶粒尺寸的减小,全位错的形成和运动变得困难甚至不可能,纳米结构金属更容易生成不全位错.在高分辨TEM图像观察实验中发现了大量孪晶或层错,也证实了不全位错的存在.着重讨论了晶界发射不全位错的形核、增殖以及在塑性变形过程中所起的作用.研究了纳米结构金属中的位错动力学,采用分子动力学模拟和高分辨透射电镜方法从不同层面上揭示了位错的形核、增殖、运动以及相互作用等过程.最后简单介绍了位错柏氏矢量以及密度的相关定量分析,其相关参数的表征对进一步弄清纳米结构金属的塑性变形机制具有重要意义.     

从零维到一维递变氧化锡纳米材料的可控制备

为了研究纳米半导体材料的量子限域效应与形貌和结构的关系,本文以SnCl4.5H2O和不同的有机酸以及不同的胺类有机物为反应物,通过溶剂热法制备了不同形貌的氧化锡纳米材料。在其它实验条件相同的前提下,通过配制不同的反应物体系,通过在同一反应体系中经过不同的溶剂热反应时间,均成功获得了从零维到一维递变的不同长径比的氧化锡纳米材料,包括纳米点、纳米棒、纳米线等。本文还尝试了在同一反应体系中使用不同的表面活性剂的方法,虽然没有获得从零维到一维递变的产物,但产物仍然具有不同形貌。     

Superior electrocatalytic activity of mesoporous Au film templated from diblock copolymer micelles

Mesoporous Au films consisting of a network of interconnected Au ligaments around ultra-large pores were found to exhibit a promising electrocatalytic activity towards sluggish reactions. Mesoporous Au films with pore sizes up to 25 nm were successfully fabricated using a polymeric micelle approach. A superior catalytic activity of the mesoporous Au films towards methanol oxidation was confirmed, which was thoroughly analyzed and compared with that of other Au materials. An intrinsic investigation on the high catalytic activity revealed that the superior performance of the as-prepared mesoporous Au film was related to its unique atomic structures around the mesopores with well-crystallized facets and several step/kink sites on the Au surfaces. These findings showcase a strategic and feasible design for preparing highly active Au-based catalysts that could be used as promising candidates in electrocatalytic applications.

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Effect of mean stress on fatigue properties of 1800 MPa-class spring steels

Fatigue tests were conducted for 1800 MPa-class spring steels at various stress ratios. For comparison, similar fatigue tests were conducted for conventional steels whose tensile strength was lower than 1200 MPa. The spring steels exhibited fish-eye fractures, and the origins of these fractures were oxide, TiN and the matrix itself. In contrast, the conventional steels never exhibited fish-eye fractures. The fatigue strength of these steels decreased monotonously as the stress ratio increased, when the fatigue strength was evaluated in terms of stress amplitude. However, the fatigue strength degradation was less than that expected from a modified-Goodman line, and the best fit line was obtained by connecting the fatigue limit at zero mean stress to true fracture strength instead of tensile strength. This research also reviewed application of a power low to the stress ratio effect evaluation. In these results, the difference between the spring and conventional steels was negligible.