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利用X射线吸收精细结构(XAFS)方法研究机械合金化制备的Fe100-xCux(x=0,10,20,40,60,70,80,100,x为原子百分比)合金中Fe和Cu原子的局域环境结构.对于Fe100-xCux(x≥40)二元混合物,球磨160h后,Fe原子的近邻配位结构从bcc转变为fcc,但Cu原子的近邻结构保持其fcc不变.与之相反,在Fe80Cu20和Fe90Cu10(x≤20)合金中,Fe原子的近邻配位保持其bcc结构而Cu原子的近邻配位结构从fcc转变为bcc结构.XAFS结果还表明,fcc结构的Fe100-xCux样品中Fe的无序因子σ(0.0099nm)比bcc结构的Fe100-xCux中的σ(0.0081nm)大得多;并且在机械合金化Fe100-xCux(x≥40)样品中Fe原子的σ(0.0099nm)比其Cu原子的σ(0.0089nm)大.这表明机械合金化Fe100-xCux样品中Fe和Cu原子可以有相同的局域结构环境但不是均匀的过饱和固溶体,而是由Fe富集区和Cu富集区组成的合金.我们提出互扩散和诱导相变机理来解释在球磨过程中Fe100-xCux合金产生从bcc到fcc和从fcc到bcc变化的结构相变
关键词:
XAFS
100-xCux合金')" href="#">Fe100-xCux合金
机械合金化 相似文献
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利用扩展x射线吸收精细结构和x射线衍射研究了机械合金化制备的体心立方(bcc)的亚稳态Fe80Cu20合金固溶体的结构随退火温度的变化特点.结果表明,在300—873 K温度范围内,随着退火温度的升高,bcc结构物相的晶格常数近于线性降低,这主要是由于Cu原子从bcc结构Fe80Cu20合金固溶体中逐渐偏析出来,生成面心立方(fcc)结构的Cu物相所致.经603K退火后,Cu原子的平均键长RCu—Cu增加了0.003 nm左右,大约有50%的Cu原子从bcc结构的Fe80Cu20合金固溶体中偏析出来.在773 K退火后,bcc结构Fe80Cu20合金固溶体近于完全相分离,生成了bcc结构的α-Fe与fcc结构的Cu物相.
关键词:
扩展x射线吸收精细结构
x射线衍射
80Cu20合金')" href="#">Fe80Cu20合金
机械合金化 相似文献
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本文叙述了用偏振中子衍射方法对Fe83B17非晶合金和中子衍射方法对Ni64B36非晶合金的结构研究。由实验数据计算了每种合金的偏干涉函数(PSF)Sij(Q),和偏简约径向分布函数Gij(r)。并得到原子短程结构上的各项参数。在此基础上,讨论了这一类非晶态合金的结构模型,计算了其一种模型简单单元的中子衍射散射强度,并和实验所得的结果作了比较。
关键词: 相似文献
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The structure of an amorphous alloy of Fe84B16 has been investigated by X-ray diffraction. The results suggest that the atomic distribution of amorphous Fe84B16 differs slightly from those of other amorphous systems such as amorphous Fe and Fe83P17. 相似文献
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E. Colavita M. De Crescenzi L. Papagno L.S. Caputi G. Chiarello R. Scarmozzino R. Rosei 《Solid State Communications》1982,41(7):545-548
The electronic properties of the amorphous and sintered Fe80B20 alloys have been studied by electron energy loss spectroscopy. A correlation among energy loss data and X-ray absorption near edge structures has been attempted.Structure-related effects in the electronic properties of Fe80B20 alloy have been found and discussed. 相似文献
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S. K. Sharma S. Banerjee Kuldeep Animesh K. Jain 《Applied Physics A: Materials Science & Processing》1988,45(3):217-220
Diffusion rates (D) of Au in two amorphous alloys, Fe80B20 and Fe82B18, and of Cu in amorphous Fe82B18 alloy were measured in the temperature range 546–645 K by using the technique of Rutherford backscattering spectrometry (RBS) and Auger electron spectroscopy (AES), respectively. The diffusion of Au was found to be 3 to 6 times faster in Fe80B20 than in Fe82B18, though both the alloys had almost similar crystallization temperatures. The observed differences in the diffusion rates corroborate the fact that Fe80B20 has a more open structure than Fe82B18 as revealed from the reported values of the metal packing fractions of these two alloys. Also, the diffusivities of smaller sized Cu atoms (radius: 0.128 nm) were found to be higher by more than an order of magnitude than those of larger sized Au atoms (radius: 0.146 nm), suggesting a dependence ofD on the size of the diffusing species. 相似文献