In 1952, Frank (Proc R Soc Lond Ser-Math Phys Sci 215:43–46, 1952) already postulated that Icosahedral Short Range Order (ISRO) of atoms in the liquid could possibly explain the large nucleation undercoolings measured in metallic alloys by Turnbull and Fisher (J Chem Phys 17:71–73, 1949). About thirty years later, this conjecture was proven to be key for the understanding of Quasicrystals (QC) formation (Shechtman et al. in Phys Rev Lett 53:20, 1951–3, 1984). More recently, it has been found that a few tens to thousand ppm of solute elements in Al-base and Au-base alloys can influence the nucleation and growth of the primary fcc phase via mechanisms involving ISRO and QC formation. ISRO has also been found to limit the mobility, and thus diffusion, of atoms in the liquid. This can lead to out-of-equilibrium conditions, e.g., the formation of metastable phases or supersaturated solid solution, at reduced velocity compared to alloys where ISRO is not predominantly present. Finally, there are several experimental evidences that ISRO is also responsible for twinned dendrites formation in Al alloys. The present contribution summarizes these recent findings and points out the implications that these might have in the field of solidification and additive manufacturing.

1952年，弗兰克（Proc R Soc Lond Ser-Math Phys Sci 215：43–46，1952）已经假设液体中原子的二十面体短程有序（ISRO）可能解释了Turnbull在金属合金中测得的大形核过冷度和Fisher（J Chem Phys 17：71–73，1949）。大约三十年后，这一猜想被证明是理解准晶体（QC）形成的关键（Shechtman等人。摘自Phys Rev Lett 53：20，1951-3年，1984年）。最近，已经发现Al基和Au基合金中的数十至数千ppm的溶质元素可通过涉及ISRO和QC形成的机理影响初级fcc相的成核和生长。还发现ISRO限制了液体中原子的迁移率，从而限制了扩散。与不主要存在ISRO的合金相比，这可能导致失衡的条件，例如亚稳相或过饱和固溶体的形成，速度降低。最后，有一些实验证据表明ISRO也是铝合金中双晶枝晶形成的原因。本贡献总结了这些最新发现，并指出了这些可能对固化和增材制造领域产生的影响。