The advent of additive manufacturing (AM) offers the possibility of creating high-performance metallic materials with unique microstructure. Ultrafine dislocation cell structure in AM metals is believed to play a critical role in strengthening and hardening. However, its behavior is typically considered to be associated with alloying elements. Here we report that dislocations in AM metallic materials are self-stabilized even without the alloying effect. The heating–cooling cycles that are inherent to laser power-bed-fusion processes can stabilize dislocation network in situ by forming Lomer locks and a complex dislocation network. This unique dislocation assembly blocks and accumulates dislocations for strengthening and steady strain hardening, thereby rendering better material strength but several folds improvements in uniform tensile elongation compared to those made by traditional methods. The principles of dislocation manipulation and self-assembly are applicable to metals/alloys obtained by conventional routes in turn, through a simple post-cyclic deformation processing that mimics the micromechanics of AM. This work demonstrates the capability of AM to locally tune dislocation structures and achieve high-performance metallic materials.

增材制造 (AM) 的出现为创造具有独特微观结构的高性能金属材料提供了可能。AM 金属中的超细位错胞结构被认为在强化和硬化中起着关键作用。然而，它的行为通常被认为与合金元素有关。在这里我们报告说，即使没有合金化效应，AM 金属材料中的位错也是自稳定的。激光动力床融合过程固有的加热-冷却循环可以通过形成洛默锁和复杂的位错网络来原位稳定位错网络。这种独特的位错组装阻止并积累位错，以加强和稳定应变硬化，从而提供更好的材料强度，但与传统方法相比，均匀拉伸伸长率提高了几倍。位错操纵和自组装的原理依次适用于通过传统途径获得的金属/合金，通过模拟 AM 微观力学的简单后循环变形处理。这项工作证明了 AM 能够局部调整位错结构并获得高性能金属材料。