Elastic Modulus of Al-Li Alloys.

含锂铝合金是一种具有高硬度和低密度的新型航空合金。本文对研制实用Al-Li合金的基本合金系Al-Li、Al-Mg和Al-Li-Mg进行了弹性模量的测定。结果表明：（1）当Li含量达到14at%时，Al的弹性模量（E）和剪切模量（G）均增大，Al-Li二元固溶体的弹性模量可用经验公式E _（Al-Li）&gt; = 73 + 0.9C_<Li>（GPa）表示，其中纯Al的弹性模量为73 GPa，C _<Li>为Li的原子分数。(2)Mg对Al的单一添加量最高达6at%时，随着Mg浓度的增加，E和G都略有下降，但呈线性关系。二元Al-Mg合金的杨氏模量可用下列经验公式表示：E（_<Al-Mg>）= 73 - 0.1C_<Mg>（GPa）其中C _<Mg>为Mg的原子%。(3)在二元或三元合金系中出现的金属间化合物中，“-Al_3Li相有提高Al的E和G值的趋势，而T-Al_2LiMg相的影响则可以忽略不计。(4)在固溶度范围内，Li和Mg的复合添加的效果似乎是加性的，这意味着Li和Mg之间的相互作用可以忽略不计。(5)Li的加入使Al的剪切模量（G）大幅度增加，证实了运动位错与溶质（Li）气氛之间的模量效应可能产生强烈的弹性相互作用，从而成功地解释了所观察到的固溶体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.