Electrodeposition of supersaturated aluminum-based solid solutions for maximizing strength and corrosion resistance

由于α-Al中存在粗大的金属间化合物颗粒(IMP)，通过合金化再经变形和时效强化的铝不可避免地存在强度和耐腐蚀性之间的矛盾。在本研究的第一阶段，用典型的1-乙基-3-甲基咪唑氯化铵([EMIM]Cl)-氯化铝(AlCl3)离子液体(ILS)制备了Al(Fe)过饱和固溶体，其中溶解Fe2+的配位通过光谱分析和从头计算得到。透射电子显微镜和X射线衍射仪分析表明，Fe(1.5-14.1at.%)能完全溶解在α-Al中，其含量受镀液中FeCl2浓度的控制。特别是，这些具有较高Fe固溶度的Al(Fe)合金分别基于纳米压痕和循环极化曲线实现了硬度和抗点蚀性能的同步提高。此外，我们新开发的四元磷基ILS([P14，6，6，6]Cl-AlCl3)可以在室温下获得Al(Si，3-6at.%)过饱和固溶体，但其硬度和耐腐蚀性等性能有待进一步研究。

Aluminum (Al) strengthened through alloying followed by the deformation and/or aging is inherently subject to the conflict between strength and corrosion resistance due to coarse intermetallic particles (IMPs) in α-Al matrix. Accordingly, supersaturated solid solutions with a homogenous microstructure are proposed to defeat that conflict.In the first stage of this research, the Al(Fe) supersaturated solid solutions have been obtained using typical 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl)－aluminum chloride (AlCl3) ionic liquids (ILs), where the coordination of dissolving Fe2+ have been clarified by spectroscopies together with ab initio calculation. The TEM and XRD demonstrated that Fe (1.5－14.1 at.%) could completely dissolve into α-Al matrix, and its contents were controlled via iron(II) chloride (FeCl2) concentrations in baths. Especially, these Al(Fe) alloys with higher Fe solid solubility prove to attain a simultaneous improvement in hardness and pitting corrosion resistance based on nanoindentation and cyclic polarization curves respectively.In addition, our newly developed quaternary phosphonium-based ILs ([P14,6,6,6]Cl－AlCl3) could give Al(Si, 3－6 at.%) supersaturated solid solutions at room temperature, while their properties including hardness and corrosion resistance require further studies.