摘要
基于微观相场模型与反演算法,研究了中Al浓度及温度对Ni_(75)Al_xV_(25-x)合金沉淀过程的影响:在相同浓度下, L1_2与DO_(22)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, L1_2(DO_(22))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L1_2的第一近邻原子间相互作用势大于(小于) DO_(22)时, L1_2(DO_(22))优先析出;当L1_2和DO_(22)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L1_2和DO_(22)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.
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 Ni75AlxV25-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.
作者
田晓林
赵宇宏
田晋忠
侯华
Tian Xiao-Lin;Zhao Yu-Hong;Tian Jin-Zhong;Hou Hua(Material Science and Engineering Institute,North University of China,Taiyuan 030051,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2018年第23期10-17,共8页
Acta Physica Sinica
基金
国家自然科学基金(批准号:51774254
51774253
51701187
U1610123
51674226
51574207
51574206)
山西省科技重大专项(批准号:MC2016-06)资助的课题~~
关键词
第一近邻原子间相互作用势
中Al浓度
反演算法
沉淀序列
the first nearest neighbor interatomic potentials
medium Al concentration
inversion algorithm
precipitation sequence