Wilden Johanna, Yang Fan, Günther Gerrit, Russina Margarita, Kuball Alexander, Busch Ralf, Meyer Andreas
Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany.
Helmholtz-Zentrum Berlin für Materialien und Energie, 14109 Berlin, Germany.
J Phys Condens Matter. 2021 Aug 18;33(43). doi: 10.1088/1361-648X/ac1968.
The Ni self-diffusion in glass forming PdNiS, PdNiSand PdNiSmelts was probed by incoherent, quasielastic neutron scattering over a temperature range between 773 and 1023 K. The Ni self-diffusion coefficients are on a 10 m s-10 m sscale and barely change with composition. Each composition exhibits an Arrhenius-type temperature dependence of the Ni self-diffusion coefficients, which results in activation energies ranging from= 348 ± 16 meV for PdNiSto= 387 ± 6 meV for PdNiS. The structural relaxation shows a stretched exponential behavior even far above the liquidus temperatures. In addition, the viscosity of the PdNiSmelt was measured under reduced gravity conditions. The diffusion calculated from the viscosity reveals a significant deviation from the measured Ni self-diffusion by a factor between 4 and 8. This may indicate a dynamic decoupling between the atoms within the Pd-Ni-S equilibrium melts.
通过非相干准弹性中子散射，在773至1023 K的温度范围内研究了玻璃形成熔体PdNiS、PdNiS和PdNiS中的Ni自扩散。Ni自扩散系数在10⁻¹⁰ m² s⁻¹的量级，且随成分变化很小。每种成分的Ni自扩散系数都呈现出阿仑尼乌斯型温度依赖性，这导致激活能范围从PdNiS的348±16 meV到PdNiS的387±6 meV。即使在远高于液相线温度的情况下，结构弛豫也呈现出拉伸指数行为。此外，在微重力条件下测量了PdNiS熔体的粘度。根据粘度计算出的扩散与测量得到的Ni自扩散之间存在显著偏差，偏差因子在4到8之间。这可能表明在Pd-Ni-S平衡熔体中原子之间存在动态解耦。
