Steels with sub-micrometre grain sizes usually possess high toughness and strength, which makes them promising for lightweighting technologies and energy-saving strategies. So far, the industrial fabrication of ultrafine-grained (UFG) alloys, which generally relies on the manipulation of diffusional phase transformation, has been limited to steels with austenite-to-ferrite transformation^1,2,3. Moreover, the limited work hardening and uniform elongation of these UFG steels^1,4,5 hinder their widespread application. Here we report the facile mass production of UFG structures in a typical Fe–22Mn–0.6C twinning-induced plasticity steel by minor Cu alloying and manipulation of the recrystallization process through the intragranular nanoprecipitation (within 30 seconds) of a coherent disordered Cu-rich phase. The rapid and copious nanoprecipitation not only prevents the growth of the freshly recrystallized sub-micrometre grains but also enhances the thermal stability of the obtained UFG structure through the Zener pinning mechanism⁶. Moreover, owing to their full coherency and disordered nature, the precipitates exhibit weak interactions with dislocations under loading. This approach enables the preparation of a fully recrystallized UFG structure with a grain size of 800 ± 400 nanometres without the introduction of detrimental lattice defects such as brittle particles and segregated boundaries. Compared with the steel to which no Cu was added, the yield strength of the UFG structure was doubled to around 710 megapascals, with a uniform ductility of 45 per cent and a tensile strength of around 2,000 megapascals. This grain-refinement concept should be extendable to other alloy systems, and the manufacturing processes can be readily applied to existing industrial production lines.

亚微米晶粒尺寸的钢通常具有高韧性和强度，这使得它们在轻量化技术和节能策略中很有前途。到目前为止，通常依赖于扩散相变操纵的超细晶粒 (UFG) 合金的工业制造仅限于奥氏体向铁素体转变的钢^1,2,3。此外，这些 UFG 钢的有限加工硬化和均匀伸长率^1,4,5阻碍了它们的广泛应用。在这里，我们报告了在典型的 Fe-22Mn-0.6C 孪晶诱导塑性钢中通过少量 Cu 合金化和通过相干无序富 Cu 的晶内纳米沉淀（30 秒内）控制再结晶过程轻松大规模生产 UFG 结构阶段。快速而丰富的纳米沉淀不仅可以防止新再结晶的亚微米晶粒的生长，还可以通过齐纳钉扎机制提高所获得的 UFG 结构的热稳定性⁶. 此外，由于它们的完全相干性和无序性，沉淀物在负载下与位错表现出弱相互作用。这种方法能够制备晶粒尺寸为 800 ± 400 纳米的完全再结晶 UFG 结构，而不会引入有害的晶格缺陷，例如脆性颗粒和偏析边界。与未添加 Cu 的钢相比，UFG 结构的屈服强度翻了一番，达到约 710 兆帕，均匀延展性为 45%，抗拉强度约为 2,000 兆帕。这种晶粒细化概念应该可以扩展到其他合金系统，并且制造过程可以很容易地应用于现有的工业生产线。