We review recent research developments in a special class of multicomponent concentrated solid solution alloys (CSAs) – of which the recently discovered high entropy alloys (HEAs) are exemplars – that offer a new paradigm for the development of next generation structural materials. This review focuses on the role of inherent extreme chemical complexity on the phase stability, electronic, transport, and mechanical properties of this remarkable class of disordered solid solution alloys. Both experimental observations and theoretical models indicate that the phase stability of HEAs goes beyond the original conjecture that these alloys are stabilized by configurational/mixing entropy; rather, it results from competition between the homogeneously disordered phase and phase separation/intermetallic compound formation. Although the number of single-phase HEAs with equiatomic composition is limited, those that do exist often exhibit remarkable electronic, magnetic, transport, and mechanical properties. For the mechanical response, we discuss the solution strengthening mechanism which governs the strength and deformation behaviors of the CSAs, as well as the increasing evidence that low stacking fault energies (deformation twinning) plays an important role in the low temperature strength and ductility of CrMnFeCoNi related alloys. We also review the current understanding of the role of the number and type of alloy elements in determining the electronic, magnetic, and transport properties, in particular the dominant role of magnetic interactions in the properties of 3d-transition metal based alloys. Finally, we emphasize that, despite rapid progress in characterization and understanding of the phase stability and physical/mechanical responses of CSAs, there remain significant challenges to fully exploring the new paradigm that these alloys represent.

我们回顾了特殊类别的多组分浓固溶体合金（CSA）的最新研究进展-其中最近发现的高熵合金（HEA）是示例-为下一代结构材料的开发提供了新的范例。这篇综述着重介绍了固有的极端化学复杂性对这种无序固溶合金这一非凡类的相稳定性，电子，输运和机械性能的作用。实验观察和理论模型均表明，HEA的相稳定性超出了最初的推测，即这些合金可以通过构型/混合熵来稳定。相反，它是由均匀无序相与相分离/金属间化合物形成之间的竞争引起的。尽管具有等原子组成的单相HEA的数量受到限制，但确实存在的单相HEA通常表现出显着的电子，磁性，传输和机械性能。对于机械响应，我们讨论了控制CSA强度和变形行为的固溶强化机制，以及越来越多的证据表明，低堆垛层错能（变形孪晶）在CrMnFeCoNi的低温强度和延展性中起着重要作用。相关合金。我们还将回顾当前对合金元素的数量和类型在确定电子，磁性和传输性能中的作用的理解，尤其是磁性相互作用在3d过渡金属基合金性能中的主导作用。最后，我们强调，