Ca_(70)Mg_(30)金属玻璃形成过程热力学、动力学和结构特性转变机理的模拟研究  

Simulation study on thermodynamic,dynamic and structural transition mechanisms during the formation of Ca_(70)Mg_(30) metallic glass

作　　者：徐春龙[1] 侯兆阳[1] 刘让苏[2] 

机构地区：[1]长安大学应用物理系,西安710064 [2]湖南大学物理与微电子科学学院,长沙410082

出　　处：《物理学报》2012年第13期348-354,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51101022);中央高校基本科研业务费(批准号:CHD2010JC083;CHD2012JC096)资助的课题~~

摘　　要：采用分子动力学方法对Ca_(70)Mg_(30)合金快速凝固玻璃形成过程进行了计算机模拟,深入分析了液-固玻璃转变过程热力学、动力学和结构特性的转变机理,对不同方法所确立的玻璃转变温度之间的关系进行了探讨.结果表明:本模拟计算所获得的Ca_(70)Mg_(30)金属玻璃的结构因子和玻璃转变温度均与实验结果符合,而且二十面体局域结构对Ca_(70)Mg_(30_金属玻璃的形成起决定性作用.由于周围原子形成的瞬时"笼子效应",过冷液体动力学特性逐渐偏离Arrhenius规律而满足模态耦合理论的幂指数规律.动力学玻璃转变温度接近于微观结构玻璃转变温度,但高于热力学玻璃转变温度;而且它们与理想动力学玻璃转变温度之间满足Odagaki关系.The rapid quenching process of CavoMgao alloy is simulated by using the molecular dynamics method. During the liquidglass transition process, the thermodynamic, dynamic and structural transition mechanisms are investigated deeply, and the relations between glass transition temperatures determined by different methods are discussed. It is found that both the simulated structural factor of CaToMg30 metallic glass and glass transition temperature are consistent with the experimental results, and the icosahedral local configuration plays a critical role in the formation of CaToMg30 metallic glass. The dynamic property of supercooled liquid gradually deviates from the Arrhenius law and satisfies the MCT power law due to the cage effect formed by neighbor atoms. It is also found that the structural glass transition temperature is close to the dynamic one, and they are higher than the calorimetric glass transition temperature. The relationship between them and the ideal dynamic glass transition temperature satisfies the Odagaki relation.

关 键 词：金属玻璃 快速凝固 分子动力学模拟 玻璃化转变 

分 类 号：TG139.8[一般工业技术—材料科学与工程]