机械合金化合成Fe-Al系纳米材料研究进展

简述了机械合金化工艺的特点,重点介绍了机械合金化合成Fe-Al过饱和固溶体、金属间化合物、非晶态材料,以及Fe-Al金属间化合物基纳米复合材料的研究进展.并就目前研究的不足及该研究领域的发展方向提出了一些看法.     

粉末冶金制备Fe-Al金属间化合物材料研究进展

回顾了近年来用粉末冶金方法制备Fe-Al金属间化合物及其复合材料的研究进展,简述了制备Fe-Al的粉末冶金方法,如无压烧结,机械合金化,热压烧结,热等静压,自蔓延高温合成及放电等离子烧结等的特点及其应用概况,并对其未来研究与应用进行了展望.     

Fe-Al金属间化合物材料的强化机理及其高温性能研究现状

对Fe-Al金属间化合物的高温力学性能和抗氧化性能的研究现状进行了回顾.归纳和描述了固溶强化、析出强化、有序强化、弥散强化等强化机理以及Fe-Al材料抗氧化的机理.并对Fe-Al材料研究的发展进行了展望.     

氩弧熔覆Fe-Al金属间化合物复合涂层的组织与性能

为改善Fe-Al金属间化合物的力学性能及抗高温氧化性能,利用氩弧熔覆方法在Q235钢上制备了Fe-Al熔覆层和Fe-Al/Al_2O_3熔覆层。采用金相显微镜、X射线衍射仪、硬度计、磨粒磨损试验机对氩弧熔覆涂层进行显微组织结构观察和磨损性能测试。采用高温氧化试验对涂层的耐高温氧化性进行了研究。结果表明:Fe-Al熔覆层形成FeAl和Fe_3Al相,而Fe-Al/Al_2O_3熔覆涂层含有FeAl、Fe_3Al和Al_2O_3相;熔覆层的耐磨粒磨损性能优于基体且Fe-Al/Al_2O_3熔覆层优于Fe-Al熔覆层;熔覆层的耐高温氧化性能明显提高,在700℃下,Fe-Al熔覆层和Fe-Al/Al_2O_3熔覆层相比于基体分别提高了4.46和5.68倍。     

Fe-Al 基复合材料化学相容性热力学分析

Fe-Al 是一种金属间化合物新型结构材料, 利用高强度、高模量的颗粒、纤维或晶须增强是进一步改善其性能的有效途径。本文提出一种方法, 通过热力学计算预测增强相和基体的化学相容性, 以方便进一步实验研究。      

Fe-Al金属间化合物的研究进展

概述了Fe-Al金属间化合物的基本特性,简述了几种改善Fe-Al金属间化合物脆性的常规方法。详细介绍了Fe-Al金属间化合物作为高温耐磨耐蚀涂层和高温气体净化多孔材料的研究新方向,以及借助先进的定向凝固技术制备Fe-Al-Ta金属基复合材料的研究新进展,指出了当前Fe-Al金属间化合物的研究领域存在的问题及今后的主要发展方向。     

高温扩散法制备铁铝金属间化合物涂层

针对金属间化合物在工业中作为高温结构材料使用存在脆性的问题，将金属间化合物以涂层的方式应用。以Fe-Al系为研究体系，以高温扩散制备的方法获得了良好的Fe-Al金属间化合物涂层，实验结果表明，在合适的工艺参数下，所得到的涂层具有单一性，致密性且与基体结合良好，该涂层具有良好的高温耐磨，耐蚀，耐氧化等特性。     

Fe3Al金属间化合物性能特点及熔制工艺研究

叙述了金属间化合物的相关知识,介绍了Fe-Al系金属间化合物的结构特征、性能特点和应用前景,强调指出由于该材料优良的抗高温氧化性能、耐磨性和耐腐蚀性而具有重要应用价值.研究了用感应电炉在大气条件下熔炼Fe3Al金属间化合物的生产工艺过程,成功地浇注出金属铸件.     

热处理对Fe-Al/WC复合涂层的组织及磨损性能的影响

研究了300,450,550,650,800℃热处理对高速电弧喷涂Fe-Al/WC金属间化合物复合涂层的组织和滑动磨损性能的影响.结果表明,热处理后复合涂层中将析出Fe2W2C 和 Fe6W6C弥散相.450～650℃热处理后,部分Fe3Al转变成FeAl造成的点阵畸变以及Fe2W2C 和 Fe6W6C的弥散强化作用,使复合涂层的显微硬度明显提高.通过热处理提高Fe-Al/WC复合涂层的显微硬度,将提高复合涂层的耐磨性.     

3Y-TZP/Fe-Al复合材料化学相容性分析

根据热力学原理,考察了Fe-Al系金属间化合物与ZrO2陶瓷基体的化学相容性。结果表明,当Fe-Al金属间化合物中Al<42at％时,Fe-Al金属间化合物与ZrO₂基体不易发生化学反应。XRD、SEM及HREM分析验证了此结论。HREM观察表明Fe₃Al与基体3Y-TZP之间界面干净,无反应层和过渡层的存在,Fe₃Al与ZrO₂界面两侧的原子排列不是一一对应的,只是部分互相匹配,形成半共格关系。界面上品面间错配度δ=30％,界面上存在着错配位错。     

Overview of processing of nanocrystalline hydrogen storage intermetallics by mechanical alloying/milling

The objective of this article is to overview processes of mechanical alloying/milling (MA/MM), and their modifications applied to produce nanostructured single- and multi-phase intermetallics, and their composites, for hydrogen storage. In the most typical processing, MA is used as a preliminary step in synthesizing a nanostructured intermetallic powder starting from elemental metal powders. In a subsequent step, the intermetallic powder is hydrogenised under high pressure of hydrogen to produce nanostructured intermetallic hydride. A modified processing variant combines the synthesis of nanostructured intermetallic and its subsequent hydrogenising in one step by MA of elemental metal powders directly under hydrogen atmosphere to form nanostructured intermetallic hydrides (so-called Reactive Mechanical Alloying—RMA). The MM can be applied to produce nanostructured intermetallic powders from pre-alloyed intermetallic cast ingots or to manufacture nanocomposites, by mixing with dissimilar material before milling, which could be hydrogenised in a separate process. In addition, pre-alloyed bulk intermetallics can be mechanically milled directly under hydrogen atmosphere (Reactive Mechanical Milling—RMM) in order to obtain nanostructured intermetallic hydrides as a final product. All the above processes are critically discussed in the present article. The effect of nanostructurization on the hydrogen sorption/desorption characteristics of intermetallics and/or their hydrides is also discussed.     

High temperature fatigue behaviour of intermetallics

There would be considerable benefits in developing new structural materials where high use temperatures and strength coupled with low density are minimum capabilities. Nickel and titanium aluminides exhibit considerable potential for near-term application in various branches of modern industry due to the number of property advantages they possess including low density, high melting temperature, high thermal conductivity, and excellent environmental resistance, and their amenability for significant improvment in creep and fatigue resistance through alloying. Reliability of intermetallics when used as engineering materials has not yet been fully established. Ductility and fracture toughness at room and intermediate temperatures continue to be lower than the desired values for production implementation. In this paper, progress made towards improving strain-controlled fatigue resistance of nickel and titanium aluminides is outlined. The effects of manufacturing processes and micro alloying on low cycle fatigue behaviour of NiAl are addressed. The effects of microstructure, temperature of testing, section thickness, brittle to ductile transition temperature, mean stress and environment on fatigue behaviour of same γ-TiAl alloys are discussed.     

TiAl金属间化合物高温抗氧化研究进展

TiAl金属间化合物以其密度低，熔点高及高温强度较高而成为重要的结构材料，并应用于诸如汽车，飞机发动机部件，然而，其高温下抗氧化性能不足是亟待解决的关键问题之一，从TiAl高温氧化机理，添加合金元素作用以及表面技术的应用三个方面，论述了TiAl高温抗氧化研究进展，讨论了等离子渗Nb大幅度改善TiAl高温抗氧化性能的作用机制。     

Opportunities for new graphitic aluminium metal matrix composite

Abstract

Nickel coated graphite particles have been incorporated into aluminium with a second particulate phase to produce graphitic aluminium metal matrix composites (Gr A-Ni) with improved processing, wear, and scuffing resistance. Excellent wear behaviour is provided by a combination of solid lubrication by graphite as well as high temperature strengthening of the matrix alloy by nickel present as Al₃ Ni intermetallics. Applications being developed include cylinder liners, pistons, connecting rods, various types of brakes, air diffusers and bushings. Neutral buoyancy of two particles, one of which is lighter and the other heavier than the aluminium matrix alloy, makes this a readily sand and die castable material. The presence of graphite and Al₃Ni intermetallics reduces the amount of ceramic particulate required to achieve the desired wear properties, with resulting improved machinability. The composition of the material can be tailored to the application. All these factors influence the finished part cost.     

Development of intermetallic materials for aerospace systems

Abstract

Certain intermetallic materials have undergone an evolutionary process whereby application of some of them could provide major benefits in aerospace systems. The realisation of the potential of intermetallic alloys based on Ti₃Al has provided significant hope for making still greater advances in turbine performance through further developments in other intermetallic materials. However, examination of the past four years of progress toward this goal has highlighted the problem that much of the fundamental understanding of process–structure–property relationships in these materials, which is the technology base upon which their application relies, has simply not been developed and suggests that widespread implementation of these materials lies in the distant future. This paper briefly discusses the problems of employing intermetallics in aerospace systems, reviews recent research progress on selected intermetallic alloys currently under investigation as high temperature structural materials, and assesses the status of intermetallics as turbine engine materials. Specifically, advances and findings from studies carried out during the past few years on alloys of the titanium and nickel aluminides and on intermetallics that are intended for service at temperatures above 1000°C are discussed. Technical challenges and factors affecting the pace of development are highlighted throughout.

MST/1562     

Role of surface passive films in the hydrogen embrittlement of iron aluminides

The room temperature hydrogen embrittlement problem in iron aluminides has restricted their use as high temperature structural materials. Previous studies have established that surface films affect hydrogen embrittlement (HE). The effect of surface passive layer on the hydrogen embrittlement behaviour of iron aluminides has been critically reviewed in this presentation. The role of thermomechanical treatments in affecting the mechanical properties has been discussed from a processing-structure-properties correlation view point. The alloy development philosophy to yield ductile iron aluminides has been outlined based on this review. Novel iron aluminide intermetallics that are being currently synthesized and characterized along these lines at IIT Kanpur are finally introduced.     

铁铝金属间化合物高温硫化腐蚀研究进展

铁铝金属间化合物由于其优异的力学性能和抗高温氧化性有望成为新一代的高温材料,因此其抗高温硫化腐蚀性能就成为了人们研究的重点课题之一.影响铁铝金属间化合物高温硫化腐蚀的因素主要有:合金成分、腐蚀气氛、温度、预处理工艺等.主要从铁铝金属间化合物的硫化机理、铁铝金属间化合物中铝含量、添加元素、腐蚀气氛、腐蚀温度等方面讨论了铁铝金属间化合物硫化腐蚀的研究进展情况.     

Intermetallics in Magnesium Alloys

Intermetallic phases can be found in almost every magnesium alloy. These intermetallic compounds play a very important role in optimizing the microstructure and mechanical properties. The present paper reviews the effects of intermetallics in magnesium alloys mainly based on their stabilities: dissolvable intermetallics at low temperatures and thermal stable intermetallics at elevated temperatures. The effects of intermetallics are discussed in the age hardenable and creep resistant magnesium alloys, separately. Finally, the further investigations are remarked on the intermetallics, including their precipitation processes, crystal structures and crystallographic orientation relations with magnesium matrix. The aim is to supply useful information in developing new wrought and creep‐resistant magnesium alloys which will be used in the powertrain at elevated temperatures.