Demmel F
ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, United Kingdom.
J Phys Condens Matter. 2022 Jul 28;34(39). doi: 10.1088/1361-648X/ac82d8.
Nickel self-diffusion was measured for a NiSialloy in the liquid state over a temperature range of about 400 K through quasielastic neutron scattering. At the two lowest temperature points the derived diffusion coefficients deviate from a high-temperature Arrhenius-type behaviour and indicate a change in dynamics above the liquidus temperature. A fit with a power-law temperature dependence as predicted by the mode coupling theory for the liquid to glass transition can describe the diffusion coefficients quite well over the whole measured temperature range. The obtained results agree with predictions from a classical molecular dynamics (MD)-simulation, which evidenced an increasing glass forming ability with increasing silicon content. A crossover to a super-Arrhenius behaviour was reported for metallic glass formers above the liquidus temperature and the here investigated NiSi alloy demonstrates the same signature.
通过准弹性中子散射测量了一种镍硅合金在约400K温度范围内液态时的镍自扩散。在两个最低温度点，导出的扩散系数偏离了高温阿仑尼乌斯型行为，表明在液相线温度以上动力学发生了变化。用模式耦合理论预测的液体到玻璃转变的幂律温度依赖性进行拟合，可以很好地描述整个测量温度范围内的扩散系数。所得结果与经典分子动力学（MD）模拟的预测结果一致，该模拟证明了随着硅含量的增加玻璃形成能力增强。据报道，高于液相线温度时，金属玻璃形成体存在向超阿仑尼乌斯行为的转变，这里研究的镍硅合金也表现出相同的特征。
