原子间相互作用势对中Al浓度Ni75AlxV25-x合金沉淀序列的影响

基于微观相场模型与反演算法，研究了中Al浓度及温度对Ni₇₅Al_xV_25-x合金沉淀过程的影响：在相同浓度下，L1₂与DO₂₂结构的第一近邻原子间相互作用势随温度升高呈线性增加，两者呈正比的关系；但在同一温度下，L1₂（DO₂₂）结构的第一近邻原子间相互作用势随Al原子浓度的增加而增加（减少）.同时将反演得出的原子作用势代入微观相场模拟中，探讨中Al浓度合金沉淀序列与原子作用势的关系，即当L1₂的第一近邻原子间相互作用势大于（小于）DO₂₂时，L1₂（DO₂₂）优先析出；当L1₂和DO₂₂的第一近邻原子间相互作用势相等时，两者同时析出.特别地，当Al原子的浓度等于0.0589时，发现L1₂和DO₂₂同时析出.利用微观相场法反演原子间相互作用势，为判断中Al浓度合金的沉淀序列增加了可信度.

Effects of interatomic potential on precipitation sequences of medium Al concentration in Ni75AlxV25-x alloys

The study of material properties show that there is a large space and time span from the electronic level, atomic level, to molecules, clusters, mesoscopic to macroscopic continuous medium. Different levels are dealt with by using different research methods. The interatomic potential function method is an important intermediary bridging from atomic level to cluster and mesoscopic physics research. Therefore, it is not only for a research field of condensed matter physics, but also for an interdisciplinary research. The interatomic potential, as the basis of all computer simulations at an atomic level, directly affects the accuracy of simulation results. That is to say, it is a greatly significant to study the interatomic potential at the atomic level. This article is based on the inversion algorithm and microscopic phase field, and the influence of medium Al concentration and temperature on the precipitation process of Ni₇₅Al_xV_25-x alloy are studied. At the same concentration, the first nearest neighbor interatomic potential of L1₂ and DO₂₂ phase increase linearly with increasing temperature, which is proportional to each other. However, the first nearest neighbor interatomic potential for L1₂ (DO₂₂) phase increases (decreases) with the increase of Al atom concentration at a constant temperature. When the temperature is 1046.5 K and the concentration of Al is 0.06, the interatomic potential of L1₂ phase is consistent with the first principles calculation by Chen, indicating the reliability of the inversion algorithm. At the same time, the inverse interatomic potentials are taken into consideration in the microscopic phase field simulation to investigate the relationship between the precipitation sequence of the medium Al alloy and the interaction potential between atoms. That is to say, when the first neighbor interatomic potential of L1₂ is greater than (less than DO₂₂) L1₂ (DO₂₂) precipitated preferentially. The first nearest neighbor interatomic potential for L1₂ and DO₂₂ are equal, both of which are precipitated at the same time. In particular, when the concentration of Al atoms is equal to 0.0589, it is found that L1₂ and DO₂₂ are simultaneously precipitated. The precipitation mechanism of the alloy with medium Al concentration is a hybrid mechanism with both non-classical nucleation and instability decomposition characteristics. Since the precipitation mechanism of the medium-concentrated alloy is a hybrid mechanism with both non-classical nucleation and spinodal decomposition, the microscopic phase field method is used to invert the interatomic potential, which increases the reliability of the precipitation sequence of medium the Al alloy.