For decades, grain boundary engineering has proven to be one of the most effective approaches for tailoring the mechanical properties of metallic materials, although there are limits to the fineness and types of microstructures achievable, due to the rapid increase in grain size once being exposed to thermal loads (low thermal stability of crystallographic boundaries). Here, we deploy a unique chemical boundary engineering (CBE) approach, augmenting the variety in available alloy design strategies, which enables us to create a material with an ultrafine hierarchically heterogeneous microstructure even after heating to high temperatures. When applied to plain steels with carbon content of only up to 0.2 weight %, this approach yields ultimate strength levels beyond 2.0 GPa in combination with good ductility (>20%). Although demonstrated here for plain carbon steels, the CBE design approach is, in principle, applicable also to other alloys.

几十年来，尽管对金属材料的机械性能进行了限制，但晶界工程已被证明是最有效的方法之一，尽管由于暴露于金属中后晶粒尺寸的迅速增加，可获得的微观结构的细度和类型受到限制。热负荷（晶体边界的低热稳定性）。在这里，我们采用独特的化学边界工程（CBE）方法，增加了可用合金设计策略的多样性，这使我们即使在加热到高温后，也可以创建具有超细分级异质微观结构的材料。当应用于含碳量仅为0.2重量％的普通钢时，此方法可产生超过2.0 GPa的极限强度，并具有良好的延展性（> 20％）。