High Resolution Electron Microscope Study on Formation and Growth Processes of Atomic Medium Range Order in Amorphous Alloys

非晶合金中原子中程有序的形成和生长过程的高分辨率电子显微镜研究

• 批准号: 02452232
• 负责人: HIROTSU Yoshihiko
• 金额: $ 4.42万
• 依托单位: Nagaoka University of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-02452232/
• 关键词: Amorphous Alloys; Rapid Quenching; Medium Range Order; Structure Relaxation; High Resolution TEM; Nano-beam Local Analysis; ナノビ-ムアナリシス

This study has been made as a two years project study from 1990 to 1991 in order to investigate structure and morphologies of atomic medium range order (MRO) in amorphous alloys, especially to investigate its formation and growth processes. As an amorphous alloy system we chose Pd-Si system. since the system has been well known as having a lot of X-ray and neutron diffraction data. In this study, eutectic Pd_<82>Si_<18> alloy ribbons made by rapid-quenching and Pd_<82>Si_<18> thin films prepared by Ar-beam sputtering were used as specimens. Structure observations of as-formed and annealed specimens were made by high resolution electron microscopy (HREM) and analytical electron microscopy. For thinning ribbon specimens, an ion-milling equipment was used which was funded by this research project. Obtained results are as follows:(1)MRO structures were observed in both of the ribbon and sputtered specimens. Calculated HREM images based on a fcc-MRO structure model were consistent with thos … More e observed.(2)Size and distribution of MRO domains were dependent of the cooling rate in rapid-quenching or in the vapor deposition.(3)On Annealing up to 573K, a MRO domain growth was observed. At 573K the MRO domain grows to a size of about 5nm, giving a splitting of the second halo diffraction ring into two diffuse rings in the selected area diffraction. Clear fcc diffraction patterns are obtained from the domains by the nano-beam diffraction. Si atoms in the MRO domains diffuse out to the matrix region on annealing at 573K.(4)On annealing at 623K clear fcc diffraction patterns start to appear in the selected area diffraction. The precipitation of alpha-Pd with a size of about 8nm starts at this temperature.The MRO structure and its growth on annealing are observed in both ribbon and thin film specimens in the same morphology in the same temperature ranges. The "structural relaxation" in an amorphous alloy on annealing can be understood as a phenomenon in which a free-volume reduction occurs mainly by the growth of MRO and a chemical ordering of atoms in the matrix proceeds by the local compositional variation on annealing. Less

为了研究非晶合金中原子中程有序（MRO）的结构和形貌，特别是其形成和生长过程，本文从1990年到1991年进行了为期两年的项目研究。作为非晶合金体系，我们选择了Pd-Si体系。因为该系统以拥有大量x射线和中子衍射数据而闻名。本研究以快速淬火法制备的共晶Pd_<82>Si_<18>合金带和ar束溅射法制备的Pd_<82>Si_<18>薄膜为试样。采用高分辨电子显微镜（HREM）和分析电子显微镜对成形和退火试样进行了结构观察。为了使带状样品变薄，使用了离子铣削设备，该设备由本研究项目资助。结果表明：(1)条带和溅射试样均存在MRO结构。基于fc - mro结构模型计算的HREM图像与实验结果一致。(2)在快速淬火和气相沉积过程中，MRO畴的大小和分布与冷却速率有关。(3)当退火温度达到573K时，观察到MRO结构域生长。在573K处，MRO结构域生长到约5nm的尺寸，使第二个晕衍射环在选定的区域衍射中分裂成两个扩散环。用纳米束衍射在畴内得到了清晰的fcc衍射图。在573K退火时，MRO畴中的Si原子向基体区扩散。(4)在623K退火时，在所选区域的衍射中开始出现清晰的fcc衍射图案。α - pd的析出开始于此温度，尺寸约为8nm。在相同的温度范围内，在相同形貌的带状和薄膜样品中观察到MRO结构及其退火生长。非晶态合金在退火过程中的“结构弛豫”可以理解为一种现象，其中自由体积的减小主要是由MRO的生长引起的，而基体中原子的化学排序主要是由退火过程中局部成分的变化引起的。少

项目成果

弘津 禎彦,穴澤 一則: "アモルファス合金構造の高分解能電子顕微鏡観察" 日本電子顕微鏡学会報. 25. 138-144 (1991)

Yoshihiko Hirotsu、Kazunori Anazawa：“非晶态合金结构的高分辨率电子显微镜观察”日本电子显微镜学会通报 25. 138-144 (1991)。

Y.Hirotsu,K.Anazawa and T.Okubo: "High Resolution Electron Microscope Observation of Medium Range Atomic Ordering in an Amorphous Pd-Si Alloy" Materials Trans.,JIM. 31. 573-581 (1990)

Y.Hirotsu、K.Anazawa 和 T.Okubo：“非晶态 Pd-Si 合金中中等范围原子有序性的高分辨率电子显微镜观察”Materials Trans.，JIM。

Y.Hirotsu,K.Anazawa,T.Ohkubo: "High Resolution Electron Microscope Observation of Medium Range Atomic Ordering in an Amorphous PdーSi Alloy" Materials Transactions,JIM. 31. 573-581 (1990)

Y.Hirotsu、K.Anazawa、T.Ohkubo：“非晶 Pd-Si 合金中中等范围原子有序性的高分辨率电子显微镜观察”Materials Transactions，JIM 31. 573-581 (1990)。

K.Anazawa, Y.Hirotsu and Y.Ichinose: "Electron Microscope Observation of Medium-Range Atomic Ordering in Amorphous Alloy" J.Non-Cryst. Solids, (1993) (Proceedings of 8-th Inter. Conf. on Liquid and Amorphous Metals, Wien, 1992).

K.Anazawa、Y.Hirotsu 和 Y.Ichinose：“非晶合金中中程原子有序性的电子显微镜观察”J.Non-Cryst。

K.Anazawa,Y.Hirotsu and Y.Ichinose: "High Resolution Electron Microscope Observation of Medium-Range Atomic Ordering in Amorphous Alloy" J.Non-Cryst.Solids,(1993)in press Proceedings of 8-th Inter.Conf.on Liquid and Amorphous Metals,Wien,1992.

K.Anazawa、Y.Hirotsu 和 Y.Ichinose：“非晶合金中中程原子有序的高分辨率电子显微镜观察”J.Non-Cryst.Solids，（1993）第 8 届国际会议论文集。