The fundamental origins of the stability of the (Pd-Ni)80P 20 bulk metallic glasses (BMGs), a prototype for a whole class of BMG formers, were explored. While much of the properties of their BMGs have been characterized, their glass-stability have not been explained in terms of the atomic and electronic structure. The local structure around all three constituent atoms was obtained, in a complementary way, using extended X-ray absorption fine structure (EXAFS), to probe the nearest neighbor environment of the metals, and extended energy loss fine structure (EXELFS), to investigate the environment around P. The occupied electronic structure was investigated using X-ray photoelectron spectroscopy (XPS). The (Pd-Ni)80P20 BMGs receive their stability from cumulative, and interrelated, effects of both atomic and electronic origin. The stability of the (Pd-Ni)80P20 BMGs can be explained in terms of the stability of Pd60Ni20P 20 and Pd30Ni50P20, glasses at the end of BMG formation, The atomic structure in these alloys is very similar to those of the binary phosphide crystals near x = 0 and x = 80, which are trigonal prisms of Pd or Ni atoms surrounding P atoms. Such structures are known to exist in dense, randomly-packed systems. The structure of the best glass former in this series, Pd40Ni40P20 is further described by a weighted average of those of Pd30Ni 50P20 and Pd60Ni20P20. Bonding states present only in the ternary alloys were found and point to a further stabilization of the system through a negative heat of mixing between Pd and Ni atoms, The Nagel and Tauc criterion, correlating a decrease in the density of states at the Fermi level with an increase in the glass stability, was consistent with greater stability of the PdxNi (80−x)P20 glasses with respect to the binary alloys of P. A valence electron concentration of 1.8 e/a, which ensures the superpositioning of the first peak in the structure factor with twice the Fermi momentum, was used to calculate the interatomic potential of these alloys. The importance of Pd to the stability of the alloys is evidenced by the fact that replacing Ni with Pd places the nearest neighbor distances at more attractive positions in this potential.
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机译：探索了（Pd-Ni） 80 P 20 大块金属玻璃（BMGs）的稳定性的基本起源，BMG是一类完整的BMG成形器的原型。尽管已对其BMG的许多特性进行了表征，但仍未从原子和电子结构方面解释其玻璃稳定性。使用扩展的X射线吸收精细结构（EXAFS）以互补的方式获得了所有三个组成原子周围的局部结构，以探测金属的最近邻域环境，并使用扩展的能量损失精细结构（EXELFS）进行了研究使用X射线光电子能谱（XPS）对占据的电子结构进行了研究。 （Pd-Ni） 80 P 20 BMG从原子和电子起源的累积且相互关联的作用中获得稳定性。 （Pd-Ni） 80 P 20 BMG的稳定性可以用Pd 60 Ni 20的稳定性来解释。 P 20 和Pd 30 Ni 50 P 20 ，在BMG形成的末期，这些合金中的原子结构与x = 0和x = 80附近的二元磷化物晶体非常相似，它们是P原子或P原子周围的Ni原子的三棱柱。已知这种结构存在于密集的，随机堆积的系统中。 Pd 40 Ni 40 P 20 系列中最好的玻璃形成剂的结构进一步用Pd < sub> 30 Ni 50 P 20 和Pd 60 Ni 20 P 20 < / sub>。发现仅存在于三元合金中的键合状态，并指出通过Pd和Ni原子之间的负混合热（ Nagel和Tauc 准则）使体系进一步稳定，这与密度的降低相关费米能级的玻璃稳定性增加与Pd x Ni （80−x） P 20 的稳定性更高相一致对于P的二元合金，使用价电子浓度为1.8 e / a的电子来计算这些合金的原子间电势，该价电子浓度可确保结构因子中的第一个峰以两倍的费米动量叠加。 。 Pd对合金稳定性的重要性可通过以下事实得到证明：用Pd替代Ni会将最接近的邻居距离放置在此电位中更具吸引力的位置。
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