Relationships between the Valence Electron Structures of Precipitated Phases and Heat Stability of Al-Cu-Mg-Ag Alloys

Liu Siqi; Qu Hua; Dong Xiaochao; Shen Xiaolu

doi:10.15980/j.tzzz.2013.08.030

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Relationships between the Valence Electron Structures of Precipitated Phases and Heat Stability of Al-Cu-Mg-Ag Alloys
Vol. 33, Issue 8, Pages: 772-775(2013)
Published： 2013 ，
DOI： 10.15980/j.tzzz.2013.08.030

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[1]刘斯琦,屈华,董晓超,申晓璐.Al-Cu-Mg-Ag合金强化相价电子结构与热稳定性[J].特种铸造及有色合金,2013,33(08):772-775.

Liu Siqi, Qu Hua, Dong Xiaochao, et al. Relationships between the Valence Electron Structures of Precipitated Phases and Heat Stability of Al-Cu-Mg-Ag Alloys. [J]. Special Casting & Nonferrous Alloys 33(8):772-775(2013)
[1]刘斯琦,屈华,董晓超,申晓璐.Al-Cu-Mg-Ag合金强化相价电子结构与热稳定性[J].特种铸造及有色合金,2013,33(08):772-775. DOI： 10.15980/j.tzzz.2013.08.030.

Liu Siqi, Qu Hua, Dong Xiaochao, et al. Relationships between the Valence Electron Structures of Precipitated Phases and Heat Stability of Al-Cu-Mg-Ag Alloys. [J]. Special Casting & Nonferrous Alloys 33(8):772-775(2013) DOI： 10.15980/j.tzzz.2013.08.030.

摘要

基于固体与分子经验电子理论

计算了Al-Cu-Mg-Ag合金中Ω、S与θ′相的价电子结构

用强化相最强共价键的共价电子对数nA分析并研究了Ω、S、θ′相与合金热稳定性的关系。结果表明

Ω、S与θ′相最强键共价电子对数nA分别为0.6591、0.5626、0.4917;Ω、S与θ′相最强键均远强于合金基体α-Al相的最强键

这是Al-Cu-Mg-Ag合金第二相强化的微观本质;Ω相耐热性高于θ′相与S相的原因在于Ω相原子所成共价键键强优于θ′与S相的共价键键强

这也是为获得具有良好高温性能的Al-Cu-Mg-Ag合金应尽量抑制θ′、S相形核

促进Ω相形核的原因。

Abstract

Based on the empirical electron theory of solids and molecules

the valence electron structures of Ω、S and θ’ in Al-Cu-Mg-Ag alloys were calculated

and the relationship between the phases of Ω、S with θ’ and heat stability was analyzed with the help of the covalence electron pairs n A of the strongest covalence bond.It is shown that the value of nA of Ω、S and θ’ is 0.659 1

0.562 6 and 0.491 7

respectively

which is far bigger than that of the matrix α-Al and responsible for the second phase strengthening.The heat stability of Ω is higher than that of S and θ’

which is attributed to the higher covalence bond strength of Ω than that of S and θ’

so the nucleation of S and θ’ should be restrained to promote the nucleation of Ω as possible as to prepare Al-Cu-Mg-Ag alloys with better high-temperature properties.