机械合金化制备MOSi2基复合材料

总结了近年来国内外大于机械合金化制备MoSi2基复合材料的研究成果，重点讨论了MoSi2的概械合金化合成过程和机理，以及机械合金化制备的MoSi2基复合材料的力学性能。机械合金化是一种合成MoSi2及其复合材料的行之有效的方法，其合成过程和机理与球磨条件有关，系统地研究了不同增强体对MoSi2的机械合金化合成过程和机理的影响是必要的，利用微合金化，合金化和复合化三方面的综合作用将成为改善MoSi2基复合材料性能的新发展趋势。     

Characterization of Al/SiC Nanocomposite Prepared by Mechanical Alloying Process Using Artificial Neural Network Model

An artificial neural network model was developed for modeling of the effects of mechanical alloying process parameters including milling time, milling speed, and ball-to-powder weight ratio on the crystallite size and lattice strain of the aluminum for Al/SiC nanocomposite powders. A Multilayer Perceptron (MLP) and Radial Basis Function (RBF) networks were used. It was found that MLP network yields better results compared to RBF network with a high correlation coefficients. The neural network model in agreement with other experimental results and theories was shown the variations of the crystallite size and lattice strain of the aluminum against the process parameters.     

机械合金化方法制备的Nd（Fe,V,Ti）12Ny磁体的结构与磁性

采用Ｘ射线和磁性测量研究了退火机械合金化ＮｄＦｅ１０．５＋０．５ｘＶ（１－Ｘ）Ｔｉｘ合金相的形成和磁学性能。根据Ｘ射线和初始交流磁化的结果作出了ＴｈＭｎ１２结构１－１２相的形成与钛的含量,退火温度的关系图。     

(FeAl)_(1-x)Ni_x和(FeAl_3)_(1-x)Ni_x机械合金化研究

为了研究按摩尔分数(FeAl)1-xNix(x=0.4,0.6)和(FeAl3)1-xNi(x=0.1,0.3)配比的粉体在机械合金化过程中的结构演变,采用X射线衍射(XRD)对球磨样品进行分析。结果表明:球磨50h后的产物主要由Fe和Al的原子比来决定,Ni的成分含量大小对主要产物基本没有影响。     

Phase Development and Crystallization Kinetics of NiTi Prepared by Mechanical Alloying

NiTi alloy is produced by mechanical alloying(MA). It becomes amorphous after milling for enough time, such as 100 h in this paper. DSC measurement shows that the crystallization temperature is 676 K for the amorphous powder. Activation energy of crystallization is 199.98kJ/mol for MA powder, which is lower than that of amorphous prepared by magnetron sputtering.Avrami parameter of crystallization is 1.07.     

TiC/Fe-Al原位复合材料制备及其显微结构

本文研究了用废弃的钢和球墨铸铁以及钛铝添加剂为原料,经熔炼和热处理制备TiC/Fe3Al复合材料的工艺过程.用光学显微镜、XRD等方法观察了复合材料的相组成、显微结构(TiC颗粒的大小和形状),进而分析了原料成分、热处理时间和温度对原位反应、TiC颗粒的生成及显微结构的影响规律.     

Mechanical Alloying of Co and Al Powders

1.IntroductionMechanical alloying is one of the effec-tive methods to prepare amorphous alloys[1].This method was first used by Koch etal.to prepare the Ni_(60)Nb_(40)amorphous alloy[2].Since then many other amorphousbinary alloys have been prepared by the     

Injection Molding of W-Ni-Fe Nanocomposite Powder Prepared by Mechanical Alloying

［1］R.M.German: Powder Injection Molding, 1990, MPIF,Princeton, NJ. ［2］R.M.German: Advances in Powder Metallurgy, 1991,4, 183. ［3］Xuanhui QU, Jinglian FAN, Yimin LI and Baiyun HUANG: Trans.of Nonferrous Metals Society of China, 2000, 10(2), 32. ［4］Jinglian FAN, Baiyun HUANG and Xuanhui QU:Trans. of Nonferrous Metals Society of China, 1999,9(1), 93. ［5］Xuanhui QU, Jinglian FAN, Yimin LI and Baiyun HUANG: Acta Metall. Sin. (English Letters), 2000,13(3), 917.     

Structure and Magnetic Properties of Powders Prepared by Mechanically Alloying 50Fe + 25Al + 25Si Mixtures

A 50Fe + 25Al + 25Si powder mixture was mechanically alloyed in a high-energy ball mill, and the products of the solid-state reactions were characterized by x-ray diffraction and magnetic measurements. The results show that the process involves the formation of a metastable bcc FeAl,Si solid solution, which decomposes into the ordered phases FeAl_{1 – x} Si _x (B2 structure) and FeSi (B20) upon heating to 700°C or long-term milling. The observed effect of milling on the magnetic properties of the powders indicates that the proportion of the ferromagnetic component in the alloy decreases with increasing milling time as a result of the ordering of the solid solution and the formation of the B2 and B20 paramagnetic phases.     

Hard Magnetic Properties of Sm-Fe-C Based Alloys Prepared by Mechanical Alloying

1. IntroductionHigh performance of hard magnet depends sensitively on illtrinsic magnetic properties of intermetallics, microstructure and compositions of allOys. NdzFel'C compound has outstanding intrinsic magnetic properties close to those of NdZFe14Bcompoundll]. SmZFe14C has an anisotropy easy phasewhich is not favorable for preparing the hard magnets.Illtroduction of illterstitial carbon atoms into SmZFe17compound with ThZZnl7-type structure results in adramatic enhancemellt of hard…     

机械合金化制备Cu-Fe过饱和固溶体及其时效分解

采用机械合金化工艺制备Cu-xFe(x=1,2,4,质量分数/%)过饱和固溶体,研究时效对其硬度和导电性能的影响.X-ray衍射分析结果表明:机械合金化显著提高了Fe在Cu中的固溶度,Cu-4Fe复合粉末经32h球磨.Fe完全固溶于Cu基体中,此时Cu晶粒尺寸为20nm,点阵常数降低到0.3621nm.硬度和导电率测试结果表明:时效处理能促进过饱和固溶体发生分解,Cu-4Fe过饱和固溶体冷压成型压坯在400℃保温8h后显微硬度HV由时效前的175降低到96,电导率由35%IACS(国际退火铜标准)提高到60%IACS.     

Microstructure Evolution Behavior of Metastable SiBCN Ceramics Prepared by Mechanical Alloying

正The fully dense amorphous Si-B-C-N monoliths were fabricated at 1000°-1600°C under5 GPa for 30 min where the mechanically alloyed amorphous Si-B-C-N powders were used as raw material.Crystallization and microstructure evolution of the prepared ceramics were investigated     

Microstructure and Mechanical Properties of Al-4.9Ni-4.9Ti Alloy Prepared by Mechanical Alloying

Mechanically alloyed Al-4.9Ni-4.9Ti powders were prepared by milling mixed aluminium, titanium and nickel powders, and then consolidated by hot hydrostatic extrusion. The microstructures of milled powders and extruded bars were characterized by X-ray diffraction and transmission eIectron microscopy observation. The results show that mechanical alloying and consolidating processes have great effects on the microstructures and mechanical properties of extruded materials. Polycrystalline materials having an ultrafine grain size may be prepared by mechanical alloying. The strength and thermal stability are improved with the increasing of processing time of mechanical alloying, since grain size decreases and volume fraction of dispersoids increases as milling time increased     

机械合金化制备NiAl(Cr,Nb)粉体

采用机械合金化的方法制备NiAl(Cr,Nb)金属间化合物粉末。以Ni、Al、Cr和Nb的粉末为原料,按原子分数Ni-38Al-5Nb-5Cr配比,研究其机械合金化过程,并采用XRD,SEM,DSC等分析手段对粉末的结构、颗粒形貌及热稳定性能等进行表征。结果表明:复合粉末在球磨10h后初步合成了NiAl(Cr,Nb),随球磨时间的延长,粉末有细化的趋势,最终产物多为规则的近球形。     

Structure and Thermal Stability of Co60Ge40 Prepared by Mechanical Alloying

The phase composition and structure of Co₆₀Ge₄₀ prepared by mechanical alloying followed by heat treatment are studied by x-ray diffraction, x-ray microanalysis, differential scanning calorimetry, and scanning electron microscopy. The results indicate that milling a 60 : 40 mixture of Co and Ge for 2 h leads to the formation of phase-pure, nanocrystalline -Co₅Ge₃ (B8₂ structure). This phase is chemically inhomogeneous and metastable. On heating to 720°C, it transforms into a homogeneous, equilibrium phase of -Co₅Ge₃. The transformation into the stable phase occurs through a two-phase state, involving the formation of the orthorhombic phase Co₂Ge. At t 630°C, Co₂Ge dissolves in -Co₅Ge₃.     

机械合金化方法制备AlxCoCrCu0.5FeNi高熵合金组织结构和性能研究

采用机械合金化和真空热压烧结方法制备了Al_xCoCrCu_(0.5)FeNi高熵合金,研究Al含量对合金系的晶体结构、显微组织、硬度、压缩性能以及摩擦磨损行为的影响。球磨60h和真空热压烧结后的晶体结构均为FCC和BCC双相结构,但相对含量发生变化。Al含量的增加使合金塑性降低,硬度和强度增大,低Al含量的Al_0、Al_(0.5)合金塑性好,强度低,压缩量高达30%和25.6%;高Al含量的Al_(1.0)、Al_(1.5)合金塑性较差,强度高,压缩强度达到1855MPa和2083 MPa,原子半径大的Al含量增加造成严重的晶格畸变,使固溶强化效应增加是合金硬度和强度升高的主要原因。随着Al含量的增加,合金的断裂方式由韧性断裂向脆性断裂转变。合金的耐磨性与硬度呈正相关关系,Al_0、Al_(0.5)、Al_(1.0)的磨损机制为黏着磨损与磨粒磨损,Al_(1.5)合金则为磨粒磨损。     

不同碳化硅和球形石墨含量对混杂增强铝基复合材料力学性能的影响

目的 研究不同增强相配比对SiCp与球形石墨颗粒混杂增强铝基复合材料力学性能的影响.方法 以6092铝合金为基体,采用粉末冶金法制备了球形石墨颗粒(Gr)、SiCp单相增强以及SiCp和Gr混杂增强的铝基复合材料,通过挤压塑性变形与T6强化热处理进一步改善材料的力学性能.结果 所制备的复合材料无孔洞等缺陷,致密度达99...     

中温轧制制备镁/铝/钽多层复合材料的界面扩散与力学性能研究

目的 实现镁铝钽异种金属复合板材的制备并优化复合板材的力学性能,以获得强轻质–高抗辐射屏蔽性能的复合金属材料。方法 通过中温轧制工艺,先进行首道次大压下量轧制、随后不断提升轧制道次的方法开展Mg–Al–Ta板材轧制复合研究,分析不同轧制道次下Mg–Al–Ta的界面扩散行为。结果 通过引入Al过渡层,成功实现Mg–Al–Ta轧制复合,不同轧制道次下制备出的Mg–Al–Ta层状复合材料表面较为平整,界面处结合良好;Mg–Al和Al–Ta界面的扩散宽度均随着轧制道次的增加而增大,在1道次到5道次的轧制中,Al–Ta界面的扩散宽度由1.2 μm增大到5.18 μm,Mg–Al界面的扩散宽度由2.38 μm增大到4.25 μm,随着轧制道次的增加,界面层硬度逐渐增大;Mg–Al–Ta层状复合板材的抗拉强度随轧制道次的增加而增大,2道次和5道次轧制板材的抗拉强度分别达到293、365 MPa;轧制道次对板材的塑性影响较小,不同轧制道次的复合板材伸长率均不足1%。结论 研究结果表明,Al是互不相溶金属Mg和Ta冶金结合的有效媒介;中温轧制的热力耦合作用是实现Mg–Al–Ta板材协同变形和界面扩散的主要机制。