Zr_(55)Cu_(30)Ni_5Al_(10)大块金属玻璃的等时和等温晶化(英文)

采用差示扫描量热仪(DSC)和X射线衍射仪(XRD)研究Zr55Cu30Ni5Al10大块金属玻璃的非等温晶化转变动力学和在过冷液相区的等温晶化动力学行为。在非等温过程中,采用不同方法(Kissinger,Flynn-Wall-Ozawa和Augis-Bennett)得到的Zr55Cu30Ni5Al10大块金属玻璃平均激活能彼此之间吻合很好。此外,采用Johnson-Mehl-Avrami(JMA)模型描述Zr55Cu30Ni5Al10大块金属玻璃的等温转变动力学。研究结果表明:Zr55Cu30Ni5Al10大块金属玻璃的Avrami指数n介于2.2和2.9之间,表明其晶化机制主要是扩散控制过程。在等温晶化的过程中,晶核长大主要是三维的长程有序扩散控制的过程,平均激活能为469kJ/mol。

Isochronal and isothermal crystallization in Zr55Cu30Ni5Al10 bulk metallic glass

Non-isothermal crystallization transformation kinetics and isothermal crystallization kinetics in super-cooled liquid region(SLR) in Zr55Cu30Ni5Al10 bulk metallic glasses were studied by differential scanning calorimetry(DSC) and X-ray diffraction(XRD).In isochronal mode,the average values of activation energy in Zr55Cu30Ni5Al10 bulk metallic glass determined by different models(Kissinger method,Flynn-Wall-Ozawa method and Augis-Bennett method) are in good agreement with each other.In addition,the isothermal transformation kinetics in Zr55Cu30Ni5Al10 bulk metallic glasses was described by the Johnson-Mehl-Avrami(JMA) model.For Zr55Cu30Ni5Al10 bulk metallic glass,the Avrami exponent n ranges from 2.2 to 2.9,indicating that crystallization mechanism in the bulk metallic glass was mainly diffusion-controlled;crystal growth is controlled by long range ordering diffusion in three-dimensional growth during isothermal crystallization process.The average value of activation energy in Zr55Cu30Ni5Al10 bulk metallic glass is 469 kJ/mol in isothermal transformation process.