NiTiZrAlCuSiB块体非晶合金等温晶化动力学

Isothermal crystallization kinetics of NiTiZrAlCuSiB bulk amorphous alloy

利用铜模铸造法制备了Ni42Cu5Ti20Zr21Al8Si3.5B0.5块体非晶合金,采用示差扫描量热计(DSC)对此块体非晶合金的等温晶化动力学进行了研究。应用函数z(φ)证明了JMA模型能够用于描述所研究的Ni基非晶合金的等温晶化动力学。结果表明:该合金的等温晶化行为始于一维界面控制地形核及长大,等温晶化的主要阶段为Avrami指数大于3.0的三维形核及长大过程。等温局部晶化激活能Um0.50为561.95kJ/mol,表明该Ni基非晶合金具有很高的热稳定性。

This paper introduces the preparation of Ni42Cu5Ti20Zr21Al8Si3.5B0.5 bulk amorphous alloy by using copper mould casting,and study of the isothermal crystallization kinetics of this amorphous alloy by differential scanning calorimeter（DSC）.According to function z（φ）,the crystallization process of the Ni-based amorphous alloy can be described by JMA model.The result shows that the first stage of crystallization process is governed by one-dimensional growth and nucleation.The Avrami exponent for the main crystallization process is larger than 3.0,indicating that the main crystallization is controlled by a three-dimensional nucleation and growth.The activation energy of partial isothermal crystallization is 561.951 kJ/mol,suggesting that Ni42Cu5Ti20Zr21Al8Si3.5B0.5 bulk amorphous alloy exhibits a very high thermal stability.