摘要
通过示差扫描量热法（DSC）研究了混合稀土基MM55Al25Cu10Ni5Co5大块非晶合金的晶化动力学。结果表明：该非晶合金晶化具有明显的动力学效应；阶段激活能随晶化体积分数的增加，先迅速增加，达到最大值后缓慢下降，为典型的形核及长大机制，且形核瞬间完成，晶化以生长为主。各种表观激活能都大于单一稀土基La55Al25Cu10Ni5Co5非晶合金相应的值，表明前者比后者具有更高的热稳定性。区域Avrami指数n（x）为3．22～5．23，为三维形核与长大过程。晶化以形核率增加还是减小的方式进行，取决于晶化体积分数与晶化温度。
Crystallization kinetics of mischmetal-based bulk metallic glasses MM_ 55 Al_ 25 Cu_ 10 Ni_5Co_5 has been analyzed by differential scanning calorimetry (DSC). The results indicate that the crystallization behavior of the metallic glasses exhibit obvious kinetic effects. The local activation energy is rapidly increased to a peak value firstly, and then is gradually decreased with increasing in crystallized volume fraction, which is typical nucleation and growth mechanism, where nucleation is completed instantaneous and growth is dominant in crystallization. The apparent activation energies of the MM-based metallic glasses are superior to those of the La_ 55 Al_ 25 Cu_ 10 Ni_5Co_5 metallic glasses, showing higher thermal stability. Local Avrami exponents are calculated to be in the range of 3.22 to 5.23, which is a 3D nucleation and growth process. Crystallization transformation behavior is dependent on crystallized volume fraction and crystallized temperature.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2006年第9期544-547,共4页
Special Casting & Nonferrous Alloys
基金
辽宁省自然科学基金资助项目(20032137)
关键词
混合稀土
大块非晶合金
晶化动力学
激活能
晶化机制
Mischmetal, Bulky Metallic Glasses, Crystallization Kinetics, Activation Energy, Crystallization Mechanism
