The redistribution of C and N atoms during cryogenic treatment is crucial for the microstructure evolution and properties of high nitrogen martensitic steel. Here, the distinct redistribution behavior of C and N atoms in a martensitic stainless steel with 0.3 wt% C and 0.5 wt% N after cryogenic treatment were investigated by the atom probe tomography. Carbon clusters begin to form after cryogenic treatment at − 60 °C and gradually increase with the decrease of cryogenic treatment temperature. While Mo–N and Cr–N pairs are homogeneously distributed in the matrix even after cryogenic treatment at −120 °C, and then form enrichment phenomenon when the cryogenic temperature is deeply lowered to − 190 °C. It is found that the distinct redistributions of C and N atoms are associated with the different interaction energy between substitutional atoms and them. The stronger interaction between Cr, Mo atoms and N delays the segregation of N during the cryogenic treatment. Finally, the mechanical properties results confirmed that the deep lower cryogenic treatment is a promising method to improve the hardness and strength in the high nitrogen martensitic stainless steel.

深冷处理过程中C和N原子的重新分布对高氮马氏体钢的微观结构演变和性能至关重要。在这里，通过原子探针断层扫描研究了深冷处理后含有 0.3 wt% C 和 0.5 wt% N 的马氏体不锈钢中 C 和 N 原子的明显再分布行为。碳簇在−60 °C 深冷处理后开始形成，并随着深冷处理温度的降低而逐渐增加。而Mo-N和Cr-N对即使在-120°C深冷处理后也均匀分布在基体中，然后在深冷温度降至-190°C时形成富集现象。发现C和N原子的不同重新分布与置换原子与其之间不同的相互作用能有关。Cr、Mo 原子和 N 之间更强的相互作用延迟了 N 在低温处理过程中的偏析。最后，力学性能结果证实，深低温处理是提高高氮马氏体不锈钢硬度和强度的有效方法。