Microstructure of fragile metallic glasses inferred from ultrasound-accelerated crystallization in Pd-based metallic glasses
Microstructure of fragile metallic glasses inferred from ultrasound-accelerated crystallization in Pd-based metallic glasses
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DOI：
10.1103/physrevlett.95.245501
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发表时间：
2005-12-09
影响因子：
8.6
通讯作者：
Anazawa, K
中科院分区：
文献类型：
--
作者：
Ichitsubo, T;Matsubara, E;Anazawa, K
通过在低于（或接近）玻璃化转变温度Tg的温度下利用超声退火，我们用高分辨率电子显微镜揭示了部分结晶的Pd基金属玻璃的微观结构图案。根据观察到的微观结构，我们推断出一个合理的脆性金属玻璃的微观结构模型由强结合区包围弱结合区（WBR）。WBR在超声波振动下在如此低的温度下的结晶是由与β弛豫相关的原子跳跃的积累引起的，β弛豫与超声波应变共振。这种微观结构模型成功地说明了一个显着增加的弹性结晶后，一个小的密度变化和液体的脆性和固体的泊松比之间的相关性。
By utilizing ultrasonic annealing at a temperature below (or near) the glass transition temperature T-g, we revealed a microstructural pattern of a partially crystallized Pd-based metallic glass with a high-resolution electron microscopy. On the basis of the observed microstructure, we inferred a plausible microstructural model of fragile metallic glasses composed of strongly bonded regions surrounded by weakly bonded regions (WBRs). The crystallization in WBRs at such a low temperature under the ultrasonic vibrations is caused by accumulation of atomic jumps associated with the beta relaxation being resonant with the ultrasonic strains. This microstructural model successfully illustrates a marked increase of elasticity after crystallization with a small density change and a correlation between the fragility of the liquid and the Poisson ratio of the solid.