Nanocrystallization of Al-Ni-Y and Al-Ni-Nd Metallic Glasses
Nanocrystallization of Al-Ni-Y and Al-Ni-Nd Metallic Glasses
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DOI：
10.4028/www.scientific.net/msf.269-272.749
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发表时间：
1998-01
期刊：
影响因子：
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通讯作者：
M. Călin;U. Köster
中科院分区：
文献类型：
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作者：
M. Călin;U. Köster
用定量透射电镜研究了Al 90 Ni 6 Nd 4和Al 85 Ni 5 Y10玻璃在退火过程中的晶化行为和显微结构演变。在140°C和250°C之间的温度下进行不同时间的等温退火导致由嵌入非晶基质中的α-Al纳米晶体的精细分散体组成的部分纳米晶体显微结构。Al 85 Ni 5 Y10玻璃比Al 90 Ni 6 Nd 4玻璃具有更高的热稳定性.通过拟合测得的晶体尺寸分布，用部分结晶玻璃的结晶统计研究了成核。晶化统计表明，α-Al相是通过瞬时非均匀形核形成的，形核速率为1020 ~ 1021 m-3s-1。在开始阶段，α-Al晶体生长迅速，但由于在α-Al晶体和基体之间形成了富RE扩散势垒，Nd对α-Al晶体生长的抑制作用比Y更强。
Crystallization behavior and microstructural development during annealing of Al 90 Ni 6 Nd 4 and Al 85 Ni 5 Y 10 glasses were investigated in detail by quantitative TEM. Isothermal annealing for various periods at temperatures between 140°C and 250°C lead to partially nanocrystalline microstructures consisting of a fine dispersion of α-Al nanocrystals embedded in an amorphous matrix. The Al 85 Ni 5 Y 10 glass exhibits a higher thermal stability than Al 90 Ni 6 Nd 4 glass. Nucleation was studied by crystallization statistics of partially crystallized glasses by fitting measured crystal size distributions. Crystallization statistics revealed that the α-Al phase forms by transient heterogeneous nucleation with nucleation rates in the order of 10 20 - 10 21 m -3 s -1 . The nanocrystal growth proceeds rapidly at the beginning, but was found to slow down probably due to the formation of a RE-rich diffusion barrier between the α-Al crystals and the matrix; Nd seems to be even more effective in slowing down the growth than Y.