首页> 中文期刊> 《物理学报》 >液态结构与性质关系Ⅱ——Mg-9Al熔体的运动黏度及与熔体微观结构的关系

液态结构与性质关系Ⅱ——Mg-9Al熔体的运动黏度及与熔体微观结构的关系

         

摘要

采用坩埚扭摆振动法测量Mg-9Al熔体的运动黏度,得到890-1190K温区内高精度的黏度-温度关系曲线v(T),发现升温过程中黏度随温度升高发生异常变化,当温度升高至1000-1075 K时,黏度由快速增大转变为逐渐减小,即发生转折变化;在随后的降温和第二次升温过程中,黏度随温度变化呈指数规律单调递增(减),符合Arrhenius方程式.在实验研究基础上,采用剩余键结构模型和"平均原子集团"演变行为的计算模型讨论Mg-9A1熔体的黏度与微观结构之间的相关性,结果表明:类β相剩余键结构的基本单元中A1-Al(B)键断裂是第一次升温过程中黏度发生转折变化的本质原因;而在第一次降温和第二次升温过程中,熔体进入新的动力学平衡状态,Al原子相对均匀的分布于熔体中,Mg-Al平均原子集团的尺寸ds及包含的近程有序原子数Ns随温度变化呈单调递增(减),黏度与平均原子集团尺寸之间存在线性的函数关系v(ds),即v=vo+K·ds.这为揭示合金熔体的结构信息变化及深入认识其黏度变化特件提供了新途径.%The method of crucible rotating oscillation damping is employed to measure the kinematic viscosity of Mg-9Al melt, and the curve of viscosity v versus temperature T from 890 K to 1190 K is obtained.It is found that there is an abnormal change for the viscosity in the first heating process, i.e., when the temperature is increased to 1000-1075 K, the viscosity varies from increase to decrease.However, in the subsequent cooling process and the second heating process, the viscosity increases (decreases) monotonically according to an exponential law with temperature, which accords with the Arrhenius equation.Based on the residual bond model and the calculation model for evolution behavior of “average atomic cluster”, the correlation between viscosity and microstructure of Mg-9Al melt is discussed.The results show that the breakage of Al-Al(B) bonds in basic unit of β phase-like residual bond structures causes an abnormal change of viscosity in the first heating process; in the subsequent cooling process and the second heating process, the melt reaches a new dynamic equilibrium state, and Al atoms are uniformly distributed in the melt.At this time, the size of Mg-Al average atomic cluster ds and the number of short-range order atoms Ns inside them increase (decrease) monotonically with temperature, and the relationship between viscosity v and size of average atomic clusters ds is expressed as a linear function, i.e., v = v0 + K · ds, which presents a new way for revealing micro-structure change of alloy melt and further understanding the change characteristic of viscosity.

著录项

  • 来源
    《物理学报》 |2011年第5期|562-569|共8页
  • 作者单位

    清华大学新材料国际研发中心,北京,100084;

    清华大学新材料国际研发中心,北京,100084;

    Нayчнo-иссдeдовaтeльскыЙ,дентр"Pacплaв",Уpaльский,Госудaственный Педarorический Унивepcитет,Екaтepинбурr 620017,Poccия;

    Нayчнo-иссдeдовaтeльскыЙ,дентр"Pacплaв",Уpaльский,Госудaственный Педarorический Унивepcитет,Екaтepинбурr 620017,Poccия;

    Нayчнo-иссдeдовaтeльскыЙ,дентр"Pacплaв",Уpaльский,Госудaственный Педarorический Унивepcитет,Екaтepинбурr 620017,Poccия;

    Нayчнo-иссдeдовaтeльскыЙ,дентр"Pacплaв",Уpaльский,Госудaственный Педarorический Унивepcитет,Екaтepинбурr 620017,Poccия;

  • 原文格式 PDF
  • 正文语种 chi
  • 中图分类
  • 关键词

    合金熔体; 结构与黏度相关性; 剩余键结构; 平均原子集团模型;

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