(上海交通大学 材料科学与工程学院, 上海 200030)
摘 要: 电弧熔炼制备的(Mo0.85Nb0.15)Si2合金为MoSi2(C11b结构)和NbSi2(C40结构)两相组织。 以电弧熔炼得到的合金为母合金， 通过光学悬浮区域熔炼法，选择适当的生长速度4 mm/h制备了(Mo0.85Nb0.15)Si2单晶，单晶结构为C40结构。 对单晶在1 200～1 700 °C进行不同时间的退火处理。研究了不同热处理制度对合金显微结构的影响规律。 结果表明： 经1600 °C， 6 h退火处理后， 在合金中形成了排列紧密、 方向取向相同的全片层状结构，片层间距为200～300 nm。 经EDS分析， 这种片层结构由贫Nb的C11b相和富Nb的C40相组成。
关键字: Mo-Si系; 单晶; 金属间化合物; 退火; 显微结构
(Mo0.85Nb0.15)Si2 single crystal
（ School of Materials Science and Engineering,
Shanghai Jiaotong University, Shanghai 200030, China）
Abstract: The intermetallics of (Mo0.85Nb0.15)Si2 with duplex C11b and C40 phases was prepared by arc-melting as the alloy used for single crystal growth. (Mo0.85Nb0.15)Si2 single crystal was then prepared by using optical floating zone melting method at a rate of 4mm/h. The crystal structure of the single crystal is C40 structure. A series of heat treatments (the treatment temperature is between 1 200-1 700 °C) were conducted on the single crystal. The effect of heat treatment on microstructure was investigated in detail. A full lamellar structure was observed after annealing at 1 600 °C for 6 h, and the lamellar spacing is between 200-300 nm. EDS analysis indicates that the lamellar structure consists of C11b phase (low Nb) and C40 phase (high Nb).
Key words: Mo-Si system; single crystal; intermetallics; annealing; microstructure
