Al_3Fe价电子结构及其对Al-Fe合金性能的影响

Valence Electron Structure of Al_3Fe and Effect on Al-Fe Alloy Mechanical Properties

基于EET理论计算并分析Al3Fe的价电子结构与合金第二相强化、高温稳定性、范性的关系。结果表明,Al3Fe最强共价键(n1Al3Fe=1.0834)键合强度远大于γ-Mg17Al12(n1γ-Mg17Al12=0.3455)和Mg2Si(n1Mg2Si=0.3241)的键合强度,有利于合金强度的提高。Al3Fe的成键能力FvAl3Fe(729.87)远大于γ-Mg17Al12(Fvγ-Mg17Al12=44.22)和Mg2Si(FvMg2Si=42.76)的成键能力,有利于合金稳定性的增强。Al3Fe的晶格电子密度ρ1Al3Fe(8.6357%)小于α-Al(ρ1α-Al=15.6808)与Mg2Si(ρ1Mg2Si=21.6478)的晶格电子密度,Al3Fe晶胞中强、弱键分布nα不均,不利于合金的范性。

Based on the empirical electron theory of solids and molecules（EET）,the valence electron structure of Al3Fe phase in heat-resisting Al-Fe alloys is calculated,and the relations of the valence electron structure to the alloy second-phase strengthen,high temperature stability,toughness and ductility are systematically expressed.Calculation results indicate that the valence electron pairs on the strongest bond of Al3Fe（n1Al3Fe=1.0834） is far greater than the strongest bond of γ-Mg17Al12（n1γ-Mg17Al12=0.3455） and Mg2Si（n1Mg2Si=0.3241） which are mostly strengthen phase in traditional heat-resisting aluminum alloys,therefore Al3Fe enormously enhanced the alloy strength.Comparing the bond-forming ability Fv Al3Fe of Al3Fe（FvAl3Fe=729.87146） with the Fv value of γ-Mg17Al12（Fvγ-Mg17Al12=44.22）and Mg2Si（FvMg2Si=42.7649）,it can be found that Al3Fe is of benefit to improves the high temperature performance of Al-Fe alloys.The lattice electron density of Al3Fe（ρ1Al3Fe=8.6357%） is smaller than that of α-Al（ρ1α-Al=15.6808%） and Mg2Si（ρ1Mg2Si=21.6478%）,and the space distribution of covalent electron pairs nα on the bonds in Al3Fe is not uniform,these are not of benefit to improves plasticity of Al-Fe alloys.