Structural relaxation of nanocrystalline PdAu alloy: Probing the spectrum of potential barriers
Structural relaxation of nanocrystalline PdAu alloy: Probing the spectrum of potential barriers
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DOI：
10.1063/1.5121520
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发表时间：
2019-11
影响因子：
3.2
通讯作者：
M. Deckarm;C. Braun;R. Birringer
中科院分区：
文献类型：
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作者：
M. Deckarm;C. Braun;R. Birringer
纳米晶金属和金属玻璃的共同之处在于它们的结构和性能依赖于制备过程和后处理。根据制备条件的不同，相对于晶体基态，储存的多余焓和体积会有很大的变化。高焓或体积的材料状态的退火引起结构松弛和伴随的多余能量和体积的消耗。我们分析了纳米晶PdAu合金的体积弛豫动力学，将整个过程划分为一组独立和平行的任意时间-温度协议的反应。得到的动力学参数谱暗示了一种复杂的松弛行为，违反了时间-温度叠加和时间-时效叠加。该分析将能够重建松弛动力学背后的有效能量景观。
A commonality between nanocrystalline metals and metallic glasses is their dependence of structure and properties upon preparation history and postprocessing. Depending on preparation conditions, stored excess enthalpy and volume—relative to the crystalline ground state—can vary significantly. Annealing of material states of elevated enthalpy or volume induces structural relaxation and concomitant depletion of excess energy and volume. We analyzed the kinetics of volume relaxation in nanocrystalline PdAu alloys by partitioning the overall process into a set of independent and parallel reactions for arbitrary time-temperature protocols. The obtained spectra of kinetic parameters imply a complex relaxation behavior that violates time-temperature superposition and time aging-time superposition. The analysis will enable to reconstruct the effective energy landscape underlying the relaxation dynamics.