Boosting the applications of high nitrogen steels requires delicate control of detrimental brittle AlN precipitates which often initiate cracking and thus degrade overall mechanical performance. Here we report that stacking faults in nano-sized AlN precipitates can be activated by martensitic transformation during quenching in a high nitrogen martensitic stainless bearing steel. Atomic-scale structure and strain analyses illuminate that the planar deformation mode, which is rarely seen in inorganic AlN ceramic precipitates, is stimulated by the martensitic transformation of the steel matrix to accommodate the transformation stresses and strains at the precipitate/matrix interfaces. The critical resolved shear stresses derived from the density functional theory study are consistent with the stress arising from the martensitic transformation obtained from the phenomenological theory of martensitic crystallography combined with phase field modeling, further validating the martensitic transformation induced plastic deformation in AlN nanoprecipitates. Our finding paves a new way to mitigate the harmful effect of AlN precipitates in high nitrogen steels and enables the production of high-quality high nitrogen steels with an upper limit of Al content raised to the normal steelmaking level, which offers new guidelines for effectively reducing the production costs of high nitrogen steels.

促进高氮钢的应用需要精细控制有害的脆性 AlN 析出物，这些析出物通常会引发开裂，从而降低整体机械性能。在这里，我们报告纳米级 AlN 析出物中的堆垛层错可以通过高氮马氏体不锈钢轴承钢淬火过程中的马氏体相变激活。原子级结构和应变分析表明，在无机 AlN 陶瓷沉淀物中很少见的平面变形模式受到钢基体马氏体转变的刺激，以适应沉淀物/基体界面处的转变应力和应变。密度泛函理论研究得出的临界分辨剪应力与马氏体晶体学唯象理论结合相场建模得到的马氏体相变产生的应力一致，进一步验证了AlN纳米沉淀物中马氏体相变引起的塑性变形。我们的发现为减轻高氮钢中AlN析出物的有害影响开辟了一条新途径，使生产Al含量上限提高到正常炼钢水平的优质高氮钢成为可能，为有效降低AlN含量提供了新的指导方针。高氮钢的生产成本。进一步验证了 AlN 纳米沉淀物中马氏体相变引起的塑性变形。我们的发现为减轻高氮钢中AlN析出物的有害影响开辟了一条新途径，使生产Al含量上限提高到正常炼钢水平的优质高氮钢成为可能，为有效降低AlN含量提供了新的指导方针。高氮钢的生产成本。进一步验证了 AlN 纳米沉淀物中马氏体相变引起的塑性变形。我们的发现为减轻高氮钢中AlN析出物的有害影响开辟了一条新途径，使生产Al含量上限提高到正常炼钢水平的优质高氮钢成为可能，为有效降低AlN含量提供了新的指导方针。高氮钢的生产成本。