Elastic Modulus of Al-Li Alloys.

含锂铝合金具有高刚性、低密度等特点，在航空领域具有重要的应用前景。本文对Al-Li、Al-Mg和Al-Li- mg等合金体系进行了弹性模量的测量，这些体系是开发实用Al-Li合金的基础体系。结果表明：(1)在Al中添加14at%的Li，可提高Al的杨氏模量(E)和剪切模量(G)。纯Al的杨氏模量为73 GPa， C <Li> (GPa), C <Li>为Li的at %。(2)单次向Al中添加Mg至6at %时，随着Mg浓度的增加，E和g均有轻微的线性降低。二元Al-Mg合金的杨氏模量用经验公式表示：E (_<Al-Mg>) = 73 - 0.1 C _<Mg> (GPa)，其中C _<Mg>为Mg的原子%。(3)在二元或三元合金体系中出现的金属间化合物中，'-Al_3 Li相有增加Al的E和G的趋势，而T-Al _2 LiMg相的影响可以忽略不计。(4)在固体溶解度范围内，Li和Mg的复配作用似乎是加性的，表明Li和Mg之间的相互作用可以忽略不计。(5) Li的加入大大增加了Al的剪切模量(G)，证实了移动位错与溶质（Li）气氛之间的模量效应可能导致强弹性相互作用，这成功地解释了观察到的固溶体Al-Li合金的高温强度。

Lithium containing aluminum alloys have a potential importance as new alloys for aeronautical applications with high rigidity and low density. In the peresent work, measurements of the elastic modulus were made of such alloy systems as Al-Li, Al-Mg,and Al-Li-Mg that are the basic systems for the development of practical Al-Li alloys. The results are summarized as follows:(1) The single addition of Li to Al up to 14at% increases both the young's modulus(E) and the shear modulus(G) of Al. The young'.s modulus of the binary Al-Li solid solution is expressed by an empirical equation, E _<(Al-Li)> = 73 + 0.9 C _<Li> (GPa) where the Young's modulus of pure Al is 73 GPa, and C _<Li> is the at % of Li.(2) The single addition of Mg to Al up to 6 at% decreases, slightly but linearly with the Mg concentration, both E and G. The Young's modulus of the binary Al-Mg alloy is expressed by the following empirical equation, E (_<Al-Mg>) = 73 - 0.1 C _<Mg> (GPa) where C _<Mg> is the atomic % of Mg.(3) Among the intermetallic compounds that appear in the binary or ternary alloy systems, '-Al_3 Li phase has a tendency to increases both E and G of Al but the effects of T-Al _2 LiMg phase is negligible.(4) The effects of the complex addition of Li and Mg, within the solid solubility limits, seem to be additive, implying a negligible interaction between Li and Mg.(5) A large increase of the shear modulus(G) of Al by the addition of Li substantiates the possible stroung elastic interaction due to the modulus effects between the moving dislocations and the solute(Li) atmosphere, which successfully explain the observed high temperature strength of the solid solution Al-Li alloys.