(1. 中南大学 材料科学与工程学院，长沙 410083； 2. 教育部有色金属材料科学与工程重点实验室，长沙 410083； 3. 中国科学院 宁波材料技术与工程研究所，中国科学院磁性材料与器件重点实验室，宁波 315201)
摘 要: 通过推广二元合金自由能的模型，研究FePt纳米微粒的形状、尺寸、有序度和成分等因素对其有序化温度的影响。结果表明：相同形状的FePt纳米微粒有序化温度随着尺寸的减小而降低；在一定尺寸下，FePt纳米微粒的有序化温度会随着形状因子的增大而降低，且为球形时有序化温度最高，为正四面体时最低。在形状和尺寸确定时，FePt纳米微粒的有序化温度会随着其初始有序度的增大而降低，也会随着Fe和Pt的摩尔比偏离1:1而降低，且偏离得越多有序化温度就下降得越快。
关键字: 纳米合金；有序无序转变；材料热力学
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China; 2. Key Laboratory of Non-Ferrous Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China; 3. Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China）
Abstract:The model for calculating the free energy of binary alloy was generalized, which can be used to study the ordering temperature of FePt nanoparticles with different shapes, sizes, constituents and ordering degrees. The results show that, in a specified shape, the ordering temperature of FePt nanoparticles decreases with the decrease of size. Fixed other conditions, the ordering temperature is the highest when the nanoparticles are spherical and the lowest when the nanoparticles are in regular tetrahedron. When the shape and size are specified, the ordering temperature of FePt nanoparticles decreases with the increase of initial ordering degree, and it also decreases with the component ratios of Pt and Fe deviating from the ideal composition of 1:1.The more the component deviates, the more quickly the ordering temperature drops.
Key words: nanoalloy; order-disorder transition; thermodynamics of material
