(1. 沈阳师范大学 物理系, 沈阳 110031;
2. 中国科学院 金属研究所 材料科学国家实验室,
沈阳 110016)
摘 要: 根据分子动力学理论建立了非晶Ni64Pd16Al20的结构模型,利用Recursion方法计算了Ni64X16Al20系非晶及相应晶态的电子结构。结果表明, Ni64X16Al20合金的非晶形成能力与过渡元素局域电子态密度的双峰位置、电子得失形成的离子键及非晶与晶态合金的总结构能差有关。 局域电子态密度的结果表明, Al与过渡元素间存在电子耦合—共价相互作用,合金元素使Ni64X16Al2合金非晶形成能力从强到弱的顺序是:Ir, Pt, Rh, Pd, Au, Ag, Cu; Ni64X16Al20合金中离子键的存在使其非晶形成能力增强。非晶与晶态合金的总结构能差越小的过渡元素使其形成非晶的驱动力越强, 对非晶形成越有利, 由此得出的规律与上述共价键的作用规律一致。
关键字: 非晶结构模型; Recursion方法;电子理论; 非晶形成能力
(1. Department of Physics, Shenyang Normal University,
Shenyang 110031, China;
2. Institute of Metal Research,
Chinese Academy of Sciences,Shenyang 110016, China)
Abstract:The atom structure model of Ni64Pd16Al20 amorphous alloy was set up by using molecular dynamics theory. The electronic structure calculations of crystal and amorphous alloy Ni64X16Al20 by Recursion method reveal that the amorphous alloy forming ability is related to the location of the double-peak (or tri-peak) of local density of states (LDOS) in low energy region, electrovalent bond formed by gaining or losing electrons and the total structure energy difference of amorphous alloy Ni64X16Al20 to crystal alloy. The common conclusion drawn from LDOS and the total structure energy difference of amorphous alloy Ni64X16Al20 to crystal alloy is: when transition element Ir, Pt, Rh, Pd, Au, Ag, Cu is added into NiAl alloy, the amorphous alloy forming ability weakens in the same order. The electrovalent bond existing in Ni64X16Al20 alloy enhances the amorphous alloy forming ability too.
Key words: amorphous structure model; Recursion method; electronic theory; amorphous alloy forming ability