Diffusion controlled grain growth in primary crystallization: Avrami exponents revisited
Diffusion controlled grain growth in primary crystallization: Avrami exponents revisited
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DOI：
10.1088/0953-8984/10/17/014
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发表时间：
1998-05
期刊：
影响因子：
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通讯作者：
T. Pradell;D. Crespo;N. Clavaguera;M. Clavaguera-Mora
中科院分区：
文献类型：
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作者：
T. Pradell;D. Crespo;N. Clavaguera;M. Clavaguera-Mora
考虑了在导致纳米结构材料的非晶合金初晶化过程中发现的阿夫拉米指数的异常行为。通过在瞬态界面控制生长之后实施软碰撞扩散机制，制定了一个能够充分处理这种相变的动力学模型。还考虑了随着结晶进行成核速率的降低。对该模型与实验数据进行了比较，结果非常吻合。软碰撞扩散机制被证明是导致阿夫拉米指数异常行为的原因，而成核速率的降低是一种二阶效应。
The anomalous behaviour of the Avrami exponents found in the primary crystallization of amorphous alloys leading to nanostructured materials is considered. A kinetic model able to adequately treat such phase transformation has been formulated by means of the implementation of a soft-impingement diffusion mechanism after a transient interface controlled growth. A decrease in the nucleation rate as crystallization proceeds has also been considered. Comparison of the model with experimental data is performed, giving excellent agreement. The soft-impingement diffusion mechanism is demonstrated to be responsible for the anomalous behaviour of the Avrami exponent, the decreasing nucleation rate being a second-order effect.