机构地区: 中南大学材料科学与工程学院粉末冶金国家重点实验室
出 处: 《中南大学学报(自然科学版)》 2008年第5期962-967,共6页
摘 要: 利用铜模吸铸法制备直径为5 mm的Y41Sc15Al24Co20大块非晶合金,采用连续加热和等温加热方法对其晶化动力学行为进行研究。利用Kissinger方程得出该合金的晶化激活能为3.02 eV。用Johnson-Mehl-Avrami(JMA)方程描述合金的等温晶化过程,在不同等温温度下计算得出Avrami指数大于3.0,合金的主要晶化过程为三维形核长大过程。在Arrhenius方程的基础上,得到合金的区域Avrami指数和阶段晶化激活能随晶化体积分数变化的关系曲线。 Y41Sc15Al24Co20bulk amorphous alloy with a diameter of 5 mm was fabricated by the method of copper mould suction casting. The crystallization kinetics of the bulk amorphous alloy was investigated by differential scanning calorimetry (DSC) in the mode of continuous heating and the isothermal annealing. The activation crystallization energy is determined by Kissinger method, i.e. Ec=3.02 eV. And the isothermal kinetics is modeled by the Johnson-Mehl-Avrami (JMA) equation, the Avrami exponents are calculated to be 3.35-4.3 for different isothermal temperatures, which implies the crystallization mechanism is a three-dimensional nucleation and growth. Finally, the nucleation and growth behaviors during the isothermal crystallization can be obtained in terms of local Avrami exponent and local activation energy.