Theoretical and experimental studies of devitrification pathways in the Zr2Cu1−xPdx metallic glass system
Theoretical and experimental studies of devitrification pathways in the Zr2Cu1−xPdx metallic glass system
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DOI：
10.1016/j.actamat.2007.07.021
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发表时间：
2007-10
期刊：
影响因子：
9.4
通讯作者：
James R. Morris;M. Xu;Y. Ye;D. Sordelet;M. Kramer
中科院分区：
文献类型：
--
作者：
James R. Morris;M. Xu;Y. Ye;D. Sordelet;M. Kramer
利用非晶态合金系列模型--Zr2Cu1−xPdx(x=0，0.2 5，0.5，0.75和1)，通过与时间分辨X射线散射研究的比较，证明从头算方法可以预测脱玻璃化过程中可能的亚稳相的形成.所有成分都具有相同的平衡C11b相，但它们遵循不同的析出途径。只有x=0.5才会导致亚稳C16相的形成。这正好对应于计算表明C16相在能量上最接近稳定的C11b相。结果表明，竞争主要由电子结构而不是尺寸效应主导，C16相的有利成分在费米能区形成了一个假能隙。所有含Pd的化合物首先析出玻璃化成准晶相。基于NiTi2Oh5结构的−xPdx化合物在能量上都高于C16和C11b结构，计算结果表明稳定性不随Pd浓度的增加而增加。
Using a model amorphous alloy series, Zr2Cu1−xPdx(x =0, 0.25, 0.5, 0.75 and 1), we demonstrate that ab initio calculations can predict likely metastable phase formation during devitrification by comparing these with time-resolved X-ray scattering studies. All compositions share the same equilibrium C11bphase, yet they follow different devitrification pathways. Only x =0.5 leads to a metastable C16 phase formation. This corresponds precisely to calculations showing the C16 phase is closest in energy to the stable C11bphase. The competition is shown to be dominated by electronic structure rather than size effects, with the favored composition for the C16 phase forming a pseudo-gap at the Fermi energy. All Pd-containing compounds devitrify first into a quasicrystalline phase. Zr2Cu1−xPdxcompounds based on the NiTi2Oh5structure are higher in energy relative to the C16 and C11bstructures for all compositions, and the calculations show no increase in stability with Pd concentration.