摘要
应用以密度泛函理论和密度泛函微扰理论为基础的平面波赝势方法,利用第一性原理ABINIT软件,采用模守恒赝势和局域密度近似计算了L1_2结构Al_3Sc和Al_3Zr金属间化合物的结构和热力学性质.合金形成焓和结合能的计算结果表明,2种金属间化合物都有比较强的合金化能力,Al_3Zr较Al_3Sc具有更强的结构稳定性.通过热力学性质的计算,给出了2种金属间化合物的自由能、定容比热、熵、体积弹性模量和热膨胀率随温度的变化趋势.体积弹性模量随温度变化关系的结果表明,Al_3Sc和Al_3Zr析出相有利于提高铝合金的高温抗蠕变性能.热膨胀随温度的变化关系及Sc和Zr在Al基体中的扩散速率解释了采用Sc和Zr复合微合金化的铝基合金焊丝改善焊缝的强度和提高抗热裂能力的机理.
A first principles investigation of the structural and thermodynamic properties of A13Sc and A13Zr intermetallics has been conducted using the norm-conserving pseudopotentials within the local density approximation in the frame of the density functional theory （DFT） and the density functional perturbation theory （DFPT） with the ABINIT code. The calculated formation enthalpy and cohesive energy results show that both phases have strong alloying ability and A13Zr has a higher structural stability than A13Sc phase. By means of calculations, the relationships of the vibrational free energy constant-volume specific heats entropy bulk modulus and thermal expansion with the elevated temperatures are given. The calculated bulk modulus indicates that Al3Sc and A13Zr phases can improve the high temperature creep resistance properties of aluminum alloys. The calculated datum of the thermal expansion and the diffusion speed of Sc and Zr in A1 can explain the mechanism that the solder wire with Sc and Zr can improve the strength of welding gap and the resistance ability of hot crack.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2013年第4期501-505,共5页
Acta Metallurgica Sinica
基金
国家重点基础研究发展计划项目2011CB606403
中国科学院“十一五”信息化专项项目INFO115-B01资助~~
关键词
铝合金
第一性原理计算
结构特性
热力学特性
aluminum alloy
first-principles calculation
structural property
thermodynamic property
作者简介
张旭东，男，满族，1979年生，讲师，博士生
