The study on the electronic structure and the crystallization process of metal-metal amorphous alloys

本文研究了非晶态CuZrFe合金的电子结构及其稳定性。采用单辊法制备试样。在低Fe含量的试样中，@>D157@> D1 Fe富集.对Cu_<60>Zr_（1-x）<40>和Cu_ Zr_（1-<59>x）<40>Fe_（1-x）的穆斯堡尔谱分析结果表明，Cu_ Zr_（1-x）和Cu_ Zr_（1-x）Fe_（1-x）Fe_（1-x）的穆斯堡尔谱出现一个分裂较大的双峰。峰的形状和参数与Fe-Zr金属间化合物，特别是非晶态Fe_ Zr_3的峰相似<25><75>。结果表明，非晶态Cu_ Zr_2的电子结构与<60><40>非晶态Fe_ Zr_2的电子结构相似<60>，Zr原子分布在Fe原子周围<40>。DSC分析表明，结晶过程为一个阶段。而晶化过程中穆斯堡尔谱的变化至少表现为两个阶段。晶化前德拜温度、四极分裂和同质异能位移变化不大。在<59><40>773 K退火30 min后，非晶Cu_ Zr_Fe_1晶化。四极分裂明显减小。这意味着非晶的不对称性随着晶化而降低。晶化过程中同分异构体向正方向移动表明Fe中d电子的增加。Cu_<60-x>Zr_<40>Fe_x（1 × 20）.非晶的稳定性随Fe浓度的增加而降低。Cu_Zr_Fe_1的晶化激活能为5.8eV<59><40>，Cu_Zr_Fe_2的晶化激活能为3.9eV<40><40><20>。高Fe含量的合金很难获得非晶结构。德拜温度、四极分裂和同质异能素位移随Fe含量的增加而降低。这些变化与稳定性有关。Fe取代Cu减少了非晶中的d电子。Fe中d电子减少。为了稳定非晶结构，Fe或Cu与Zr之间的键合是必要的。成键归功于d电子。随着铁含量的增加，d电子的缺乏使非晶结构变得不稳定。

The purpose of this study is to investigate the electronic structure in amorphous CuZrFe alloys and its stability. Specimens were prepared by single roll method. In specimens with low Fe concentration @>D157@>D1Fe was enriched.1. The results on Cu_<60>Zr_<40> and Cu_<59>Zr_<40>Fe_1 : The Mossbauer spectrum showed a doublet peak whose split was large. The shape and parameters of the peak was similar to those for Fe-Zr intermetallic compounds or especially amorphous Fe_<25>Zr_<75>. From those results it is concluded that around Fe atoms Zr atoms were ditributed and that the electronic structure in amorphous Cu_<60>Zr_<40> is similar to that in amorphous Fe_<60>Zr_<40>. The crystallization process has one stage judging from DSC analysis. However the Mossbauer spectrum change during crystallization showed two stages at least. Before crystallization Debye temperature, quadrupole splitting and isomer shift changed a little. Amorphous Cu_<59>Zr_<40>Fe_1 crystallized by annealing at 773K for 30minutes. The quadrupole splitting decreased abrptly. This means that the asymmetry in amorphous decreased with crystallization. The shift of isomer shift to plus side with the crystallization indicates the increase of d electrons in Fe.2. The results on Cu_<60-x>Zr_<40>Fe_x(1 x 20). The stability of amorphous decreased with in creasing Fe concentration. The activation energy of crystallization was 5.8eV for Cu_<59>Zr_<40>Fe_1 and 3.9eV for Cu_<40>Zr_<40>Fe_<20>. It was diffcult to obtain amorphous structures with high Fe concentration. Debye temperature, quadrupole splitting and isomer shift decreased with increasing Fe. These changes are related with stability. The replacement of Fe to Cu decreases d electrons in amorphous. So d electrons in Fe decreased. To stabilize the amorphous structure the bonding between Fe or Cu and Zr is necessary. The bonding owes to d electrons. The defficiency of d electrons with increasing fe make amorphous structure unstable.