L12型铝合金的结构、弹性和电子性质的第一性原理研究

运用第一性原理方法研究了L12型铝合金相Al3Sc和Al3Zr的晶体结构、电子结构和弹性.结合能和形成能的计算表明,两种合金具有较强的合金化能力,且Al3Zr较Al3Sc具有更强的结构稳定性.电子结构分析表明,费米能级以下较多的价电子数决定了Al3Zr具有较强的结构稳定性.计算并分析比较了两种合金相的单晶弹性常数(C11,C12和C44)以及多晶弹性模量(体弹性模量B、剪切模量G、杨氏模量Y、泊松比ν和各向异性因子A).通过对比实验和其他理论计算结果,进一步分析和解释了两种合金相的力学性质.

Structural,elastic and electronic properties of L12 aluminum phases from first principles calculation

First principles calculations are performed to study structural, elastic and electronic properties of typical L12 precipitates of Al-based alloys (Al3Sc and Al3Zr). The calculated formation energy and the cohesive energy show that both typical L12 precipitates of aluminum alloys have a strong alloying ability and Al3Zr phase has a higher structural stability than Al3Sc phase. According to the calculated density of states of these phases, it is found that the higher structural stability of Al3Zr is attributed to an increase in the number of bonding electrons below Fermi level. Three independent single-crystal elastic constants (C11,C12 and C44) at zero-pressure as well as polycrystalline mechanical parameters such as bulk modulus B, shear modulus G, Young's modulus Y, Poisson's ratio ν and anisotropy value A for both phases are calculated. The mechanical properties of both phases are further analyzed and discussed in comparison with experimental observations and other theory results.