DIFFUSION AND CRYSTALLIZATION IN VACUUM-DEPOSITED AND LIQUID-QUENCHED AMORPHOUS ALLOYS

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概要

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• Structure cahnges of vacuum-deposited amorphous Au-Si and liquid-quenched amorphous Fe-B and Co-Fe-Si-B alloys by irradiation with high energy electrons have been observed by high resolution and high energy electron microscopy. The irradiation is found to induced the transformation to metastable phase and also to stable phase at much lower temperatures than those of the similar reactions by simple thermal treatment. In Au-Si, no visible structure change takes place at a temperataure lower than -120℃ even by a strong irradiation. The speed of the transformation to metastable phase by irradiation gradually increases with temperature, and precipitation of pure silicon takes place at above 0℃. The precipitation grows very fast until the matrix is covered with metastable phase. The existence of a very rapid diffusion of gold through amorphous phase and a strong tendency to maintain a homogeneous mixture within the amorphous is concluded. Detailed structure of the metastable phase has been observed as lattice images. Irradiation with no observable change at low temperature is found in all the observed materials to enhance the nucleation of crystalline phase which appears by heating after the irradiation. From the dependence on the irradiation dose and intensity, not the formation of the crystalline nucleus but the homogeneous change of the amorphous sturcture is concluded to be induced by irradiation. The enhancement of the thermal nucleation is more pronounced by the irradiation at higher temperatures. The variation of the phenomena with temperature of each reaction serves us to propose 'variable vacancy mechanism' of diffusion and crystallization in amorphous solids. The mechanism characterizes the diffusion in amorphous materials by the existence of multi-component diffusion carriers. The existence of the thermal equilibrium change among pre-existing latent vacancies, which accompanies a large change in their mobility, is suggested.

• 東北大学の論文

著者

• Yoshiie T.

  Department Of Material Physics Faculty Of Engineering Science Osaka University

• Kiritani M.

  Department Of Material Physics Faculty Of Engineering Science Osaka University

• Kiritani M.

  Department Of Electronic Engineering Hiroshima Institute Of Technology

関連論文

• Nucleation of Interstitial Type Dislocation Loops in Metals under Neutron Irradiation
• VARIABLE LATENT VACANCY MECHANISM OF DIFFUSION IN AMORPHOUS METALS
• DIFFUSION AND CRYSTALLIZATION IN VACUUM-DEPOSITED AND LIQUID-QUENCHED AMORPHOUS ALLOYS
• Defect structure development in electron irradiated Cu-Pd and Cu-Pt alloys with HVEM

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