基于纤维增强复合材料的超声振动辅助加工技术综述

纤维增强复合材料是一类使用范围不断扩大的具有优良机械性能的工程复合材料,但由于其具有各向异性及增强体纤维稳定的理化性能,使得传统金属加工方法很难对纤维增强复合材料进行高质量的加工,特别是对于以芳纶纤维等断裂伸长率较高的纤维为增强体的复合材料,存在较为严重的撕裂、毛刺和分层等加工缺陷。超声振动辅助加工是一种将超声振动附加在机械加工过程中的加工方式。超声振动的加入可使刀具与工件周期性接触,减小切削阻力,降低切削温度,可在一定程度上提高纤维增强复合材料加工的表面质量,减少加工缺陷。在介绍超声振动辅助技术的分类、系统组成和加工机理,及纤维复合材料表面质量、材料去除、加工机理和加工缺陷的基础上,从套料制孔、螺旋铣孔和轮廓铣削三类常见加工工艺方面,论述了针对纤维复合材料的超声振动辅助切削技术的国内外研究进展。基于纤维复合材料超声振动辅助切削技术的发展状况,从基础理论研究、材料表面改性和新加工工艺探索、超声振动加工系统的开发完善等方面,总结了现有研究和应用中的成果及普遍存在的问题,同时对未来研究的发展趋势做出了展望。     

Sheet metal forming at elevated temperatures

Due to the need to significantly reduce the part weights in automotive manufacturing, the use of lightweight materials becomes ever more important. Unfortunately, these materials are often associated with a limited cold formability. Due to this fact, production of large, complex sheet metal components using forming technology frequently entails increased expenditures. Moreover, processing high-strength materials requires correspondingly high processing forces and pressures. In order to find a solution to counter the disadvantages mentioned above, the use of elevated temperatures as a process parameter in forming operations represents a potential solution approach. The following paper will give an overview about research activities in the field of forming operations at elevated temperatures.     

RESEARCH AND DEVELOPMENT OF HIGH TEMPERATURE STRUCTURAL MATERIALS FOR AERO-ENGINE APPLICATIONS

The status of research, development of superalloys and materials processing ＆ fabrication technologies for aero-engine applications in China Aviation Industry, with an emphasis on recent achievements at BIAM including directionally solidified and single crystal superalloys for blade and vane applications, wrought superqlloys for aero-engine disks and rings, and powder metalurgy （PM） superalloys for high performance disk applications were described. It was also reviewed the development of new class of high temperature structural materials, such as structural intermetallics, and advanced material processing technologies including rapid solidification, spray forming and so on. The trends of research and development of the above mentioned superalloys and processing technologies are outlined. Cast, wrought and PM superalloys are the workhorse materials for the hot section of current aero-engines. New high temperature materials and advanced processing technologies have been and will be the subject of study. It is speculated that high performance, high purity and low cost superalloys and technologies will play key roles in aero-engines.     

The intelligent processing of materials: An overview and case study

The intelligent processing of materials is an emerging methodology for simulating and controlling the processing and manufacture of materials. It involves model-based process optimization, in-situ microstructure sensing, and the control of both the process variables and the performance-defining microstructural attributes of a material during its synthesis and processing. It is finding widespread application in the manufacture of electronic, photonic, and composite (i.e., high-performance) materials, as well as primary metals. Authors’ Note: This article is based on AGARD SMP lecture series 205, Smart Structures and Materials: Implications for Military Aircraft of New Generation, held in Philadelphia, Pennsylvania, on October 30–31, 1996; in Amsterdam, Netherlands, on November 18–19, 1996; and in Paris on November 21–22, 1996. Haydn N.G. Wadley earned his Ph.D. in physics at the University of Reading, England, in 1979. He is currently the Edgar A. Starke, Jr., research professor in materials science and associate dean for research at the School of Engineering and Applied Science at the University of Virginia. Dr. Wadley is a member of TMS. Ravi Vancheeswaran earned his Ph.D. in mechanical and aerospace engineering at the University of Virginia in 1996. He is currently a research assistant professor at the School of Engineering and Applied Science at the University of Virginia. Dr. Vancheeswaran is also a member of TMS.     

电磁场在材料加工中应用现状及发展趋势

电磁场作为一种可控的物理场,因其具有独特的性能而使其在材料科学研究和加工中的应用非常广泛.本文综述了电磁场在材料科学研究和加工中的应用现状及其发展趋势.最后指出电磁场传统应用技术的完善和优化、新的应用技术研究开发、复合场的应用研究将成为电磁场在材料科学研究和加工中发展方向.     

Study on the relationship between laser processing sound and material removal characteristics

Laser processing is an important manufacturing technology in machining difficult-to-cut materials. It is known that a sound is generated when laser processing is carried out, the intensity of the sound changing according to the processing conditions. The purpose of this research is to clarify experimentally the relationship between the material removal characteristics and the pressure level of the processing sound when a low and a high frequency laser beam are applied to the processing of ceramic materials.     

INTERMETALLIC ALLOYS AND COMPOSITES FOR THE 21ST CENTURY: A BASIC ENERGY SCIENCES PROGRAM OF THE U. S. DEPARTMENT OF ENERGY

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Materials science and engineering at National Taiwan University

Abstract

The history of the Department of Materials Science and Engineering at National Taiwan University and its research activity are reviewed. Research is currently concentrated in five divisions: metallic materials, polymeric materials, ceramic materials, electronic materials and materials processing.     

镁合金成形技术研究进展

镁合金材料及其成形技术的研究和开发对于扩大镁合金在我国的应用具有十分重要的意义.根据第四届中国国际压铸会议论文资料,综述了国内外镁合金材料及其成形技术的的国内外发展趋势,包括材料、成形技术及数值模拟等,展望了镁合金的开发与应用前景.     

高熵非晶材料及其增材制造技术研究进展

高熵非晶合金具有独特的物理、化学和力学性能以及更好的热稳定性,因而其制备技术成为国内外重要的研究热点之一. 然而利用传统技术制备高熵非晶材料时会产生晶粒粗大及材料浪费等缺点,难以满足工艺生产需要. 而增材制造技术的精准制造和快速冷却等特点可以解决这一问题,制备出各项性能优越的高熵非晶合金. 简要介绍了高熵非晶材料的研究体系和常用制造方法,着重阐述了高熵非晶材料的断裂强度、耐腐蚀性和热稳定性的研究,对增材制造技术的工艺特征和优势,以及利用增材制造技术制备高熵非晶合金的科学难点作出了总结. 结果表明,利用增材制造技术有利于获得致密均匀的高熵非晶材料,但对于非晶相形成的解释仅限于高熵合金4大效应.最后阐述了近年来利用常用的两种增材制造手段制造高熵非晶合金的研究,并对增材制造技术制备高熵非晶材料的发展趋势提出了展望.     

纳米材料在表面工程中应用的研究进展

综述了近年有关纳米材料在表面工程领域的研究和应用进展,介绍了纳米材料作为表面工程材料的相关特性和制备方法,重点地纳米材料在表面精加工,制备功能涂料、功能复合镀层、功能性薄膜材料、热喷涂材料和作为抗磨减摩润滑材料的应用研究进展。     

Mimicry of natural material designs and processes

Biological structural materials, although composed of unremarkable substances synthesized at low temperatures, often exhibit superior mechanical properties. In particular, the quality in which nearly all biologically derived materials excel is toughness. The advantageous mechanical properties are attributable to the hierarchical, composite, structural arrangements common to biological systems. Materials scientists and engineers have increasingly recognized that biological designs or processing approaches applied to man-made materials (biomimesis) may offer improvements in performance over conventional designs and fabrication methods. In this survey, the structures and processing routes of marine shells, avian eggshells, wood, bone, and insect cuticle are briefly reviewed, and biomimesis research inspired by these materials is discussed. In addition, this paper describes and summarizes the applications of biomineralization, self-assembly, and templating with proteins to the fabrication of thin ceramic films and nanostructure devices.     

硬脆材料的磨粒加工仿真技术

单晶硅等硬脆材料具有高硬度、低断裂韧性等特性,属于难加工材料,其加工表面易产生微裂纹、亚表面损伤层等缺陷。影响硬脆材料磨粒加工过程的因素复杂,一般用仿真技术来研究磨粒加工硬脆材料的去除机理等。本文概述了硬脆材料磨粒加工相关研究中广泛应用的网格法、无网格法以及网格与无网格结合方法,对比分析各仿真方法的特点及存在的局限性并提出未来的研究方向。      

Processing maps: A status report

In the last two decades, processing maps have been developed on a wide variety of materials including metals and alloys, metal matrix composites, and aluminides, and applied to optimizing hot workability of materials and for process design in bulk metal working. Processing maps consist of a superimposition of efficiency of power dissipation and the instability maps, the former revealing the “safe” domain for processing and the latter setting the limits for avoiding undesirable microstructures. The dynamic materials model, which forms the basis for processing maps, is discussed in relation to other materials models. The application of dynamical systems principles to understanding of deterministic chaos in the system will help in achieving a greater degree of microstructural control during processing. The patterns in the hot working behavior as revealed by the processing maps of several classes of alloys relevant to technology are reviewed briefly. Processing maps have also been applied to analyze several industrial problems including process optimization, product property control, and defect avoidance, and a few examples are listed. With the processing maps reaching a matured stage as an effective tool for optimizing materials workability, expert systems and artificial neural network models are being developed to aid and prompt novice engineers to design and optimize metal processing without the immediate availability of a domain expert, and the directions of research in this area are outlined.     

金属材料的组织演化机理:基于同步辐射光源的原位研究进展

金属材料是一类最重要的承力结构材料,其通常在复杂的恶劣环境下服役.为获得优良的材料性能,金属材料的制造工艺和流程往往较为复杂,并且包含众多工序,深入研究并掌握制备过程中和复杂服役环境下的金属材料组织与缺陷的演化机理是提高材料性能和确保材料安全服役的重要基础.同步辐射光源具备的高时空分辨率为研究金属材料组织结构微观动力学...     

Using torque sensitivity analysis in accessing Friction Stir Welding/Processing conditions

The use of Friction Stir Processing (FSP) techniques for the joining and/or transforming of metallic materials is being object of intensive research since the earliest development of the Friction Stir Welding (FSW) technology in 1991. Despite of this, an accurate understanding of the main welding/processing mechanisms and its relation with the process parameters is still missing. Current paper intends to provide some further insight on this subject by discussing the relations between processing parameters, classified as independent variables, and the corresponding welding results, classified as dependent variables, using torque sensitivity analysis. The relation between base materials properties, plate thickness, welding conditions and torque evolution were also explored, which constitutes a novelty relative to the previous studies on this subject.     

搅拌摩擦加工研究进展

搅拌摩擦加工(FSP),是一种新型的材料塑性变形加工方法,它是在搅拌摩擦焊(FSW)的基础上提出的。从发明至今,研究者已经成功将FSP用于铸造金属微观组织细化、超塑性材料的制备、材料表面改性以及各种复合材料的制备中。搅拌摩擦加工工艺与搅拌摩擦焊接工艺基本相同,工艺参数对搅拌摩擦加工材料质量有很大的影响。综述了搅拌摩擦加工近年来的研究进展,主要包括不添加增强相的FSP和添加增强相的FSP两大类。其中不添加增强相的FSP主要有铸造金属微观组织细化和超塑性材料制备,添加增强相的FSP主要有材料表面改性和复合材料制备。搅拌摩擦加工制备复合材料根据添加相是否与基体反应生成增强相,又分为非原位合成法制备复合材料与原位合成法制备复合材料。文中对以上内容分别进行了总结与评述,最后指出了FSP今后发展应用的方向。     

Recent advances of electromagnetic interference shielding Mg matrix materials and their processings: A review

In terms of lightweight electromagnetic interference (EMI) shielding structural materials, Mg matrix materials have proven to be the best, due to their exciting properties (e.g. low density, high specific strength, good electrical conductivity and excellent EMI shielding properties) and their wide range of applications in lightweighting in electronics, automotive and aerospace industries. Through processing, such as alloying, heat treatment, plastic deformation and composite processing, Mg matrix materials can be obtained with tailorable properties which can play a key role in designing materials for EMI shielding. This work introduces an overview of the research on the EMI shielding properties of Mg matrix materials as well as their EMI shielding mechanisms over the past few decades, focused on the influence of alloying, heat treatment, plastic deformation and composite processing for the EMI shielding properties of Mg matrix materials. At the end, conclusions and future perspectives are provided.     

Advanced processing technology for high-nitrogen steels

Both high-and low-pressure processing techniques can be employed to add nitrogen to iron-based alloys at levels in excess of the equilibrium, ambient-pressure solubility limits. High-pressure techniques include high-pressure melting-solidification; powder atomization; and high-pressure, solid-state diffusion. Low-pressure techniques are centrifugal powder atomization and mechanical alloying. This article describes U.S. Bureau of Mines research on a range of processing technologies for nitrogen steels and references thermodynamic and materials characterization studies that have been completed on these materials.