纳米Fe-Cu体系的结构和电阻温度特性

Structure and resistance temperature property of nano-sized Fe-Cu system

采用机械合金化方法制备了亚稳Fe50Cu50纳米合金粉末，压片后在氩气中分别进行523K、873K热处理，利用X—ray衍射和Mossbauer效应对样品的结构和相变进行了分析结果表明，机械合金化后的样品为面心立方结构的固溶体，经523K热处理后，亚稳合金已开始分解；经873K热处理后，样品已完全转变为纳米尺寸的α-Fe和Cu的混合体。在15．295K内对热处理后样品的电阻进行了测量，结果表明，样品表现为负的电阻温度系数。

Metastable nano-sized Fe50Cu50 alloy powders were prepared by mechanical alloying mechanical alloying, followed by being pressed into pellets. The pellet specimens were heat-treated in argon atmosphere at 523 K and 873 K, respectively. The structure and phase transition were investigated using X-ray diffraction and Mossbauer effect. It was shown that the mechanically alloyed specimens were fcc solid solutions, and the metastable alloys decomposed at 523 K, and ultimately transformed into a mixture of nano-sized α-Fe and Cu at 873 K. The measurement results of resistance of the specimens show the negative resistance temperature coefficient in the temperature range from 15 K to 295 K.