块状金属纳米结构材料的研究与展望

纳米材料具有常规材料所没有的特异功能。纳米材料的制备技术和固结成形技术 ,为发展和应用新材料起着至关重要的作用。本文介绍了 6种块状金属纳米材料的直接制备技术和固结成形技术。     

Bulk Nanostructured Materials

This paper will address three topics of importance to bulk nanostructured materials. Bulk nanostructured materials are defined as bulk solids with nanoscale or partly nanoscale microstructures. This category of nanostructured materials has historical roots going back many decades but has relatively recent focus due to new discoveries of unique properties of some nanoscale materials. Bulk nanostructured materials are prepared by a variety of severe plastic deformation methods, and these will be reviewed. Powder processing to prepare bulk nanostructured materials requires that the powders be consolidated by typical combinations of pressure and temperature, the latter leading to coarsening of the microstructure. The thermal stability of nanostructured materials will also be discussed. An example of bringing nanostructured materials to applications as structural materials will be described in terms of the cryomilling of powders and their consolidation.     

Study of a Nanostructured Anatase Coating on the Rutile Surface

Russian Journal of Non-Ferrous Metals - Nanosized titanium dioxide allows solving complex engineering problems. One such a problem is the development of materials and coatings that reduce the...     

Mg-TM-Ln型镁基纳米结构材料研究

讨论了Mg-Cu-Y、Mg-Ni-Y和Mg-Zn-Y等三种重要的Mg-TM-Ln型的多组元Mg基纳米结构材料的成分构成、制备过程、微观结构和力学性能以及它们的形成机制。其中,制备方法涉及非晶部分晶化法、机械合金化/粉末冶金法(MA/PM法)和快速凝固(原子雾化)/粉末冶金法(RS/PM法)。结果表明,在Mg-Cu-Y系合金中,分布于非晶相基体之上的纳米晶体相使非晶合金的断裂应力增加。而不同成分的旋淬Mg-Cu-Y非晶条带弯曲断裂韧性的不同,很可能是由于存在于它们之中的纳米晶颗粒的性质有别而造成;在Mg-Ni-Y系合金中,Y部分地置换Ni将严重地影响其晶化行为,使得Mg-Ni-Y三元非晶合金中的纳米晶体相颗粒变得更加细小,而合金晶化行为的改变则导致了其杨氏模量的明显变化;在所有的金属合金中,RS/PMMg97Zn1Y2合金的比强度是最高的。而在所有的Mg基合金中,RS/PMMg-Zn-Y合金具有最佳的综合性能。     

Synthesis and Characterization of Nanostructured NiCrFeSiB HVOF Coating

The nickel based as-atomized thermal spray feedstock powder (NiCrFeSiB) was ball milled to produce the nanostructured powder. The feedstock powder was mechanically milled using two station planetary ball-mill. The milled and unmilled feedstock powders were coated using High-velocity oxygen fuel system to produce nanostructured and conventional coatings respectively on the carbon steel substrate (SA210 Grade C). The metallurgical characterization of feedstock powders and coatings were performed using scanning electron microscope, High resolution- transmission electron microscope coupled with energy dispersive spectroscopy and X-ray diffraction techniques. The developed coatings were mechanically characterized by microhardness test and bond strength measurement techniques. The porosity of the coating was measured by analyzing the optical microscope image using the image-J software. In this study, nanostructured coatings exhibited higher hardness, less porous and better bond strength compared to conventional coating.     

纳米材料性能及其应用前景

介绍国内外纳米材料的研究概况，综述了纳米材料的制备技术、微观结构、微观性能以及在各个领域中的应用前景。     

纳米结构材料的现状及发展

介绍了纳米结构材料的性能和生产工艺方法，分析了纳米结构材料市场发展状况。     

超细铝粉浆配制金属闪光漆研究

采用自制超细铝粉配制成铝银浆,通过实验,给出了金属漆配制,涂装工艺,并对其性能进行了常规检测,其指标基本符合车用标准。实验发现,采用两种不同粒径的铝粉浆将可以平衡漆膜光学和物理指标;在基料树脂中加入25％的氨基树脂可提高漆膜性能;在漆料中加入适量助剂可提高铝粉在漆膜中平行排列的效果;溶剂的使用应使施工黏度达到16～18s;涂装工艺采用湿碰湿（2C2B）涂装,并控制闪蒸时间,可获得满意的漆膜效果。     

金属材料的成分设计

本文阐述了金属材料成分设计的重要性以及纯金属和合金成分设计的一般方法和规律,表明了作者的某些观点和看法。     

适用于煤气化系统的高温金属材料

简要介绍了煤气化技术和气化炉中的高温腐蚀性气氛.论述了煤气化系统中使用的金属材料及其遇到的问题.重点介绍了MGH956合金在煤气化系统中表现出来的优异的腐蚀抗力和使用性能.     

Pd-Cu-Ni-P Bulk Metallic Glass: A Very Low Damping Material

The present work addresses damping experiments performed in a Pd-Cu-Ni-P bulk metallic glass. After an appropriated thermal treatment, this material exhibits a very low damping coefficient, down to 10⁻⁶. This result is discussed considering the different possible origins of the damping phenomena: thermoelasticity, energy dissipation by electrons, phonons, defects, and residual stresses. Thermoelasticity and defects appear to be the most important sources of mechanical damping. This article is based on a presentation given in the symposium entitled “Bulk Metallic Glasses IV,” which occurred February 25−March 1, 2007 during the TMS Annual Meeting in Orlando, Florida under the auspices of the TMS/ASM Mechanical Behavior of Materials Committee.     

金属阳极钌钛涂层的研究

涂层是金属阳极制造的关键工艺,涂层的性能将直接影响阳极的使用寿命和质量。本文结合氯碱工业用涂钌钛阳极的生产实际,对提高涂层性能的途径进行了探讨。     

Deformation Features for Highly Porous Metallic Materials

Ultralight metallic structural materials based on foamed nichrome and cellular sandwiches made from stainless steel are prepared with a porosity of 90-95% and high specific strength indices are obtained. Effects of loss of stability and nonuniform deformation over the height are detected with compression of foamed nichrome and nickel, and they are duplicated with radial deformation of model honeycomb structures. This makes it possible to establish that on the basis of these phenomena there are local structural arches in the material. A model is suggested for an arched structural element and the elastic problem is resolved for its deformation that adequately describes the effect of loss of stability.     

Optimized Electromagnetic Fields Levitate Bulk Metallic Materials

The bulk metallic electromagnetic levitation technique has a promising application prospect in condensed physics and materials science. In order to resolve the problem of weak levitation force and the small size of samples, an optimized solution based on finite element analysis (FEA) is developed to seek the best electromagnetic field distribution in the levitation zone. The influence of material properties on the distribution of magnetic flux density, surface pressure, and the Lorentz force were studied by the FEA method with various sample sizes of titanium and copper balls. The levitation capability of cylindrical coil system which consists of a single-layer coil with an inner diameter of 30 mm and the levitated object with a diameter of 20 mm was analyzed. To keep a balance between the turn number and increment efficiency of force, the best number of 7 turns is confirmed. Then, two types of optimized coils were predicted by numerical simulations, and the levitation force is improved drastically. The double-layer coil displays an outstanding levitation capability owing to the strong electromagnetic field generated by multilayer turns. In addition, 5 to 50 g aluminum, titanium, copper, and nickel are levitated by the above three kinds of coils and the levitation capacities are validated from the recorded data of the minimum operating current that can levitate the samples. The experimental results show good agreements with the simulation results, and the minimum current for optimized coils is reduced efficiently.     

低维纳米材料的制备方法与金属纳米材料

纳米材料的纳米晶粒和高浓度晶界特征以及由此而产生的小尺寸量子效应和晶界效应，使其具有特殊的力、电、磁、声、光等性能。晶粒尺度在1～100nm范围内的金属纳米材料具有强度、硬度高，韧性好、损耗低，比热高，磁化率高、矫顽力高等特性，是具有广阔应用前景的新型材料。综述了目前国内外低维纳米材料的制备方法、表征技术和研究成果，并对这些方法和成果进行了比较研究，着重介绍用这些方法所制备的金属纳米材料及其在科学领域中的应用。     

Prediction of Metallic Materials Relaxation at Elevated Temperature

A simple stress relaxation function is presented for metallic materials at elevated temperature. The function is derived from a more general physical‐phenomenological model describing the mechanical behaviour of metallic materials under creep conditions. The physical‐phenomenological model is represented by a simple Theological diagram with the minimum possible number of rheological elements. The creep function has only three fitting parameters whose dependencies on stress are presented by simple functions. The resulting stress relaxation curves agree with the experiments, not only the ones carried out in the laboratory but also the ones taken from literature.     

2002年云南金属材料与加工年评

从材料的制备工艺、性能和应用，即黑色金属、有色金属、稀贵金属和陶瓷材料等方面评述了云南省材料与加工的研究状况，就其研究方向提出一些看法。     

扫描电镜在金属材料检测中的应用

文章主要介绍了扫描电镜的原理及其特点,并讲述了其在金属材料检测中的应用,包括微观组织观察、点扫描、线扫描与面扫描、断口分析和EBSD分析等方面。