共查询到19条相似文献,搜索用时 85 毫秒
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Fe-Cu二元互不溶体系合金在机械合金化过程中形成纳米晶过饱和固溶体,并显示出与其微米尺度结构合金所不同的独特性能。综述了近年来Fe-Cu二元互不溶体系中纳米晶过饱和固溶体的机械合金化研究进展,着重介绍了Fe-Cu纳米晶过饱和固溶体的形成机理及其力学和物理性能等。 相似文献
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综述了近年来互不溶体系轴承合金机械合金化的研究进展,着重介绍了机械合金化过程中纳米相复合结构的转变机制和具有纳米相复合结构的互不溶体系轴承合金的热稳定性和力学性能。 相似文献
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NiAl金属间化合物的研究进展 总被引:4,自引:0,他引:4
对NiAl金属间化合物的国内外研究现状如改善NiAl合金力学性能和高温抗氧化性能等所 采用的合金化、制备多相合金、制备复合材料、定向凝固、机械合金化、热压及热等静压、燃烧合成、 微晶涂层等工艺以及NiAl合金的超塑性行为进行了系统综述,着重介绍并论述了合金化及定向 凝固等工艺。此外,还介绍了NiAl合金的固溶强化磁行为。 相似文献
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在高纯氩气保护下采用高能球磨法对原子组成为Fe44Co44Zr3.5Nb3.5B4Cu1的混合粉末进行机械合金化(MA)实验,成功地制取了非晶合金粉末.利用X射线衍射(XRD)、扫描电镜(SEM)、差热分析(DTA)对其进行测试,结果表明:Fe-Co系的混合粉末在MA过程中,通过原子之间的相互固溶、扩散可形成非晶态.此非晶合金的形成是晶粒细化、球磨过程中的缺陷、应力和致密堆垛结构等多种因素综合作用的结果,这与机械合金化的合成机理之一的扩散型机制相吻合.用非晶化的热力学条件判据和动力学条件判据对此合金进行计算,其结果也表明此合金已非晶化. 相似文献
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本文对一种氧化物弥散强化镍基高温合金的机械合金化工艺、过程及原理进行了研究。研究表明,用Cr-Ni-Al-Ti-Zr-B中间合金来代替现行的、采用多种中间合金的选配方案,可以同样获得机械合金化的效果,并能最终实现γ′沉淀相及Y_2O_3弥散相在同一合金中的均匀分布。机械合金化是在保护气氛下将各种原始粉末在高能球磨机中反复冷焊-破碎过程,以获得含有弥散质点的机械固溶体粉末。X光和扫描电镜分析表明,在“机械固溶体”中各种元素已基本合金化,同时也存在一定的微区成分偏离,但可以通过改进合金化工艺及热挤压和热处理来消除。本文也对影响机械合金化的因素进行了分析。 相似文献
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机械合金化在Fe-Si合金制备中的应用 总被引:1,自引:0,他引:1
机械合金化是一种新的材料制备方法, 近年来在功能材料的制备中得到了广泛的应用. 该文简要回顾了机械合金化的发展历史, 阐述了机械合金化的原理及反应机制, 介绍了机械合金化技术在过饱和固溶体、非晶、纳米晶及金属间化合物等领域的应用状况. 指出机械合金化过程的热力学和动力学研究及合金相结构、性能与球磨工艺条件之间的规律是今后研究的重点, 后续处理工艺的改进是产品实现从实验室向工业应用转变的重要保证. 相似文献
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机械合金化诱导难互溶系Cu-Cr合金固溶度扩展的研究 总被引:4,自引:2,他引:2
采用机械合金化工艺制备Cu-4%Cr和Cu-7%Cr(原子分数)二元合金粉末,利用XRD,SEM和TEM研究机械合金化过程中粉末的微观形貌和显微组织结构,测量了不同球磨时间粉末的氧含量以及显微硬度.结果表明:在一定的球磨时间内,Cu-Cr合金粉末随着高能球磨的进行,晶粒逐渐细化至纳米尺寸,晶格畸变增加,但进一步球磨会导致铜的晶格常数有所增加,畸变降低.实验证明,在固态下几乎不互溶的Cu-Cr合金,经球磨40 h的机械合金化,Cr在Cu中的固溶度明显提高. 相似文献
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The phase transformations which occur in the Ti-Nb binary alloy system have been discussed in two recent papers. The phase
relationships were investigated by varying alloy composition and thermal history. In this paper, these results are summarized
in complete and thermodynamically consistent calculations of the stable and metastable phase diagrams. The calculations of
the metastable equilibria are relevant to the Ti-V and Ti-Mo systems, as well as to several other titanium and zirconium-based
transition metal alloy systems.
Formerly with the National Bureau of Standards, Gaithersburg, MD 20899. 相似文献
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镁的合金化与合金相图 总被引:18,自引:2,他引:16
论文分析了镁基合金二元和多元相图的研究现状;指出了镁合金在合金化中存在的问题。在此基础上探讨了在镁合金的设计与研究过程中如何进行相图的研究。指出由6-10个元素组成镁合金集团进行合金相图的实验测定和热力学计算的方案是可行的。 相似文献
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M. Sherif El-Eskandarany J. Saida A. Inoue 《Metallurgical and Materials Transactions A》2003,34(4):893-898
A single glassy phase of Zr70Pd20Ni10 alloy powder was synthesized by mechanical alloying the elemental powders for 48 hours, using a high-energy ball-milling
technique. The obtained glassy phase transformed into a metastable big-cube phase upon increasing the ball-milling time (100
hours). After 150 hours of milling, a complete glass-metastable-phase transformation was achieved, and the end product was
nanocrystalline big-cube powder, which has a lattice constant of 1.23 nm. As the ball-milling time was further increased the
big-cube phase could no longer withstand the mechanical deformation that was generated by the milling media and transformed
into a new metastable phase of nanocrystalline fcc Zr70Pd20Ni10. The lattice constant of this metastable phase was calculated to be 0.455 nm. The reported metastable phases here are new
and have never been, so far as we know, reported for the ternary Zr-Pd-Ni system, or its binary-phase relations. 相似文献
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非混溶系Al—20%Pb合金的机械合金化研究 总被引:1,自引:1,他引:0
通过机械合经对非混溶系Al-20%Pb合金的结构,形态和组元的分布进行了研究,「实验证实MA可获得成分无效偏析的混溶体。DSC分析表明机械混溶体是一种具有高储存能的非平衡态合金。 相似文献
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A. Y. Badmos H. K. D. H. Bhadeshia 《Metallurgical and Materials Transactions A》1997,28(11):2189-2194
Normal thermodynamic theory for solutions begins with the mixing of component atoms. Many solutions are, however, prepared
by mixing together lumps of the components, each of which might contain millions of identical atoms. We examine here the way
in which a solution evolves from these large clusters of components, from a purely thermodynamic point of view. There are
some interesting results, including the prediction that solution formation by the mechanical alloying of solid components
cannot occur unless there is a gain in coherency as the particles become small. The nature of the barrier to mechanical alloying
is discovered. There is also the possibility of a metastable state prior to the achievement of full solution, when the component
atoms prefer like-neighbors. 相似文献
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Formation of metastable and equilibrium phases during mechanical alloying of Al and Mg powders 总被引:1,自引:0,他引:1
D. L. Zhang T. B. Massalski M. R. Paruchuri 《Metallurgical and Materials Transactions A》1994,25(1):73-79
Formation of metastable and equilibrium phases during mechanical alloying by high-energy ball milling of mixtures of Al and
Mg powders was studied using X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). Different phases were
formed, depending on the overall composition of the starting mixture. A powder mixture of nominal composition 40 at. pct Mg
gradually becomes converted into a metastable supersaturated Al(Mg) face-centered cubic (fcc) solid solution having approximately
23 at. pct Mg in solution. Powder mixtures of nominal composition of 60 or 80 at. pct Mg gradually transform into the equilibrium
γ phase during mechanical alloying, but for the composition of 80 at. pct Mg, some unalloyed Mg is left. Mechanical alloying
is comparable to rapid solidification in producing metastable phases in the Al-Mg system, except that mechanical alloying
is likely to leave some residual unalloyed elements. There is no indication of the formation of the other equilibrium phase,
the β phase, present in the phase diagram. The reason why the β phase does not form is thought to be related to the complex
structure and a very large unit cell associated with this phase. However, the β phase is obtained if the mechanical alloyed
powders are heat-treated at higher temperatures. 相似文献
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准晶是一种结构特殊的固态有序相.其特殊的原子排列方式可能会使其具有较高的储氢性能.研究目的是获得Ti系准晶,并对其电化学储氢性能进行研究.采用铸造法炼制合金,准晶难以形成.因此采用首先通过机械合金化获得非平衡态合金,然后对非平衡态合金进行不同温度热处理来获得准晶的技术路线.采用机械合金化制备了Ti42.5 Zr42.5 Ni15非晶.在机械合金化过程中要注意气体保护,否则难以形成非晶.将非晶合金在530℃处理2h后,在基体中出现了准晶,此时的基体为准晶和晶态混合物,准晶占大部分.经750℃处理2h后,合金基体中只有晶态存在.对不同状态合金进行了电化学储氢特性测量.对于非晶、准晶、晶态三状态合金,其电化学储氢均存在一个活化过程.非晶态的容量最高,其次为准晶态,晶态最低. 相似文献