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采用X射线衍射(XRD)、差热分析(DTA)和电子显微镜研究Ni60Nb40和Ni40Nb60快淬非晶的晶化行为。结果表明,在10 K/min加热速率下采用差热分析测得Ni60Nb40和Ni40Nb60的非晶初始晶化温度分别为913和917K,且两种非晶样品在低于各自初始晶化温度退火时均发生了晶化。其中,Ni60Nb40样品经763 K退火48 h后仍保持非晶态,而经873 K退火1 h后,则析出面心立方纳米晶颗粒;对于Ni40Nb60非晶合金,在763 K温度下退火48 h就发生晶化,析出面心立方纳米相。晶化样品中均发生明显的成分偏聚现象。结合金属玻璃中的微结构与动力学不均匀性以及β弛豫过程,初步探讨Ni60Nb40和Ni40Nb60快淬非晶相关低温纳米晶化行为的内在机制。
The crystallization behavior of Ni60Nb40 and Ni40Nb60 quenched amorphous alloys was investigated by X-ray diffraction (XRD), differential thermal analysis (DTA) and electron microscopy. The results show that the amorphous initial crystallization temperatures of Ni60Nb40 and Ni40Nb60 are 913 and 917K, respectively, at a heating rate of 10 K / min, and both amorphous samples anneal below the initial crystallization temperature Crystallization occurred. Among them, the Ni60Nb40 samples annealed at 763 K for 48 h remained amorphous, while annealed at 873 K for 1 h, then precipitated face-centered cubic nanocrystalline particles; for Ni40Nb60 amorphous alloy, annealed at 763 K for 48 h Crystallization occurs, precipitation of face-centered cubic nanophases. Crystallization of the sample significant segregation occurred in the phenomenon. Combining the microstructure and kinetic heterogeneity in metal glass and the β relaxation process, the intrinsic mechanism of nanocrystallization at low temperature during quenching amorphous Ni60Nb40 and Ni40Nb60 was discussed.