摘要
采用第一性原理平面波赝势方法,计算Al^-Zn-Mg-Cu系高强铝合金主要中间相Al_2Cu,Al_2Cu Mg和Mg Zn_2的结合能、形成焓、弹性常数及态密度。计算结果表明:3相结合能按Mg Zn_2>Al_2Cu Mg>Al_2Cu顺序递减;形成焓按Mg Zn_2>Al_2Cu>Al_2Cu Mg顺序递减;Al_2Cu具有很高的弹性模量,同时具有一定的塑性,可以作为合金的强化相;Al_2Cu Mg是典型的脆性相,并表现出明显的各向异性,容易诱导产生裂纹;Mg Zn_2具有良好的塑性,同时熔点较低,是合金的主要强化相;3相中均存在离子键的相互作用,提高了结构稳定性;通过适当降低Cu,Mg含量,提高Zn的含量,有利于生成Mg Zn_2相,进一步提高合金的综合性能。
Structural stabilities, mechanical properties and electronic structures of Al2Cu, Al2CuMg and MgZn2 intermetallics in Al-Zn-Mg-Cu aluminum alloys were determined from the first-principle calculations by VASP based on the density functional theory. The re-sults show that the cohesive energy （ Ecoh ） decreases in the order MgZn2 〉 Al2CuMg 〉 Al2Cu, whereas the formation enthalpy （ΔH） decreases in the order MgZn2 〉 Al2Cu 〉 Al2CuMg. Al2Cu can act as a strengthening phase for its ductile and high Young’ s modulus. The Al2 CuMg phase exhibits elastic anisotropy and may act as a crack initiation point. MgZn2 has good plasticity and low melting point, which is the main strengthening phase in the Al-Zn-Mg-Cu aluminum alloys. Metallic bonding mode coexists with a fractional ionic in-teraction in Al2Cu, Al2CuMg and MgZn2 , and that improves the structural stability. In order to improve the alloys’ performance fur-ther, the generation of MgZn2 phase should be promoted by increasing Zn content while Mg and Cu contents are decreased properly.
出处
《航空材料学报》
EI
CAS
CSCD
北大核心
2016年第6期1-8,共8页
Journal of Aeronautical Materials
基金
国家重点基础研究发展计划资助项目(2012CB619505)
关键词
高强铝合金
中间相
第一性原理
力学性能
high strength aluminum alloy
intermetallics
first-principles
mechanical properties
作者简介
通讯作者：范世通（1985-）,男,博士,主要从事高性能铝合金材料性能研究,（E-mail）fanstone95@163.com.
