非晶合金非等温晶化激活能的计算方法

介绍了计算非晶合金非等温晶化激活能的各类方法,指出等转化法是最可靠的一类方法.对等转化法中的各种具体计算方法,进行了分析并将它们分为A、B、C三种类型.类型A的计算公式在推导过程未作任何数学近似,而类型B则引入了温度积分的近似解析解,类型C以不同加热速度条件下所测得的晶化放热峰顶温度处的晶化体积分数是一个常数为前提假设,可以使用类型A和类型B的所有计算公式.类型C的前提假设与实际晶化过程往往有出入而产生误差.当热分析曲线基线难于精确确定时,用类型B中的公式计算出的激活能比类型A计算出的精度高.

Computation methods of activation energy of amorphous alloy with non-isothermal crystallization

Several methods for calculation of activation energy of amorphous alloy with non-isothermal crystallization were introduced.It was pointed out that model-free isoconversion methods were the most reliable ones.A large number of these isoconversion methods were analyzed and then classified into three types as A,B and C.With the type-A,there was no mathematical approximations made in its derivation;for the type-B,an approximation was made for the temperature integral;and in the type-C,all computation formulae in the methods of type-A and B might be used on the premise that the maximum rate of a transformation occurs at a fixed volume fraction of crystallization in spite of any heating rate.In principle,the type-C method could be used both in the method of type-A and type-B.However,for all considered reaction functions,there would be always a small variation in the transformed volume fraction at maximum reaction rate and with different heating rates.Thus,a small error would take place.In case where some uncertainty over baselines of the thermal analysis data existed,type-B method would often be more accurate than type-A method.