过冷液态金属热力学性质的变分计算

VARIATIONAL CALCULATION OF THERMODYNAMIC PROPERTIES OF SUPERCOOLED LIQUID METALS

本文用Gibbs-Bogoliubov热力学变分计算方法,以硬球(HS)体系为参考体系,对第Ⅲ族中Al,Ga,Tl及过渡金属Ti进行了过冷液态热力学性质的计算,算出平均原子体积Ω,Helmholtz自由能F,内能E及熵S,并得到等容比热c_ν;等温体弹性模量B_T,热膨胀系数α_p和等压比热c_p.从c_p-T曲线得到非晶转变温度T_g。T_r(=Tg/Tm)的理论值表明了金属形成非晶的能力,和实验结果相符。

By means of the Gibbs-Bogoliubov (GB) thermodynamical variationalcalculation, the thermodynamical properties of the liquid metals as supercooled sta-te, such as Al, Ga, Tl in the 3rd family of periodic table and transition metal Tiwere calculated using the hard-sphere (HS) system as reference. The values of meanatomic volume, Helmholtz free energy, internal energy and entropy as well asspecific heat at constant volume, isothermal bulk modulus, thermal expansion co-efficient and specific heat under constant pressure were determined. The glass tran-sition temperature, T_g, is easily obtained from c_p-T plot. The glass forming abili-ty for metal can be predicted with T_g/T_m, which is in agreement with the experi-mental results.