(1. 大連理工大學(xué) 材料科學(xué)與工程學(xué)院，大連 116024；
2. 中國(guó)科學(xué)院 金屬研究所 沈陽(yáng)材料科學(xué)國(guó)家實(shí)驗(yàn)室，沈陽(yáng) 110016；
3. 大連理工大學(xué) 物理與光電工程學(xué)院，大連 116024)
摘 要: 采用X射線衍射(XRD)、差熱分析(DTA)和電子顯微鏡研究Ni60Nb40和Ni40Nb60快淬非晶的晶化行為。結(jié)果表明，在10 K/min加熱速率下采用差熱分析測(cè)得Ni60Nb40和Ni40Nb60的非晶初始晶化溫度分別為913和917 K，且兩種非晶樣品在低于各自初始晶化溫度退火時(shí)均發(fā)生了晶化。其中，Ni60Nb40樣品經(jīng)763 K退火48 h后仍保持非晶態(tài)，而經(jīng)873 K退火1 h后，則析出面心立方納米晶顆粒；對(duì)于Ni40Nb60非晶合金，在763 K溫度下退火48 h就發(fā)生晶化，析出面心立方納米相。晶化樣品中均發(fā)生明顯的成分偏聚現(xiàn)象。結(jié)合金屬玻璃中的微結(jié)構(gòu)與動(dòng)力學(xué)不均勻性以及β弛豫過(guò)程，初步探討Ni60Nb40和Ni40Nb60快淬非晶相關(guān)低溫納米晶化行為的內(nèi)在機(jī)制。
關(guān)鍵字: Ni60Nb40；Ni40Nb60；非晶；納米晶；熱穩(wěn)定性
（1. School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China;
2. Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences,
Shenyang 110016, China;
3. School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024, China）
Abstract:The low-temperature crystallization behavior of Ni60Nb40 and Nb60Ni40 melt-spun metallic glasses was studied by X-ray diffractometry (XRD), differential thermal analysis (DTA) and electron microscopy. The results show that the initial crystallization temperatures of Ni60Nb40 and Ni40Nb60 metallic glasses are 913 K and 917 K, respectively, at a constant heating rate of 10 K/min. After annealing at temperatures below initial crystallization temperature, these two metallic glasses crystallize. Ni60Nb40 metallic glass preserves the amorphous state after annealing at 763 K for 48 h, while nanocrystals with face-centered cubic structure forms in the amorphous matrix after annealing at 873 K for 1 h. Nanocrystallization of Nb60Ni40 metallic glass occurs when the sample is annealed at 763 K for 48 h. Scanning transmission electron microscopy analysis gives convincing evidence of composition separation in these nanocrystallized microstructures, and the underlying mechanism was discussed in light of the existence of microstructural and dynamic heterogeneity and the β-relaxation process in fragile metallic glasses.
Key words: Ni60Nb40; Ni40Nb60 metallic glasses; nanocrystallization; thermal stability
