(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長(zhǎng)沙 410083； 2. 教育部有色金屬材料科學(xué)與工程重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083； 3. 中國(guó)科學(xué)院 寧波材料技術(shù)與工程研究所，中國(guó)科學(xué)院磁性材料與器件重點(diǎn)實(shí)驗(yàn)室，寧波 315201)
摘 要: 通過(guò)推廣二元合金自由能的模型，研究FePt納米微粒的形狀、尺寸、有序度和成分等因素對(duì)其有序化溫度的影響。結(jié)果表明：相同形狀的FePt納米微粒有序化溫度隨著尺寸的減小而降低；在一定尺寸下，F(xiàn)ePt納米微粒的有序化溫度會(huì)隨著形狀因子的增大而降低，且為球形時(shí)有序化溫度最高，為正四面體時(shí)最低。在形狀和尺寸確定時(shí)，F(xiàn)ePt納米微粒的有序化溫度會(huì)隨著其初始有序度的增大而降低，也會(huì)隨著Fe和Pt的摩爾比偏離1:1而降低，且偏離得越多有序化溫度就下降得越快。
關(guān)鍵字: 納米合金；有序無(wú)序轉(zhuǎn)變；材料熱力學(xué)
（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
