马氏体时效钢因其优异的强韧性平衡，在航空航天和汽车工业等领域中不可或缺。 然而，在服役过程中，循环加载诱发的包辛格效应会显著改变材料的屈服强度，进而导致尺寸精度丧失甚至早期疲劳失效，严重影响服役过程的可靠性。 当前研究对微观组织不均匀性如何调控包辛格效应仍缺乏系统认知。 通过分析 18Ni(300)钢在固溶处理(ST)及固溶+时效处理(STA)条件下的循环变形行为，结合电子背散射衍射(EBSD)与透射电镜(TEM)表征，揭示马氏体束尺寸分布不均与几何必需位错(GND)局部富集的协同作用是加剧包辛格效应的关键机制。 研究表明，通过合理热处理制度均匀化材料组织和 GND 密度是减小包辛格效应的有效途径。

Maraging steel is indispensable in aerospace, automotive, and other fields because of its excellent balance of strength and toughness. However, the Bauschinger effect, which is commonly induced by cyclic loading during service, can significantly alter a material's yield strength. This leads to a loss of dimensional accuracy and even premature fatigue failure, thereby compromising service reliability. Current research still lacks a systematic understanding of how microstructural heterogeneity regulates the Bauschinger effect. By analysing the cyclic deformation behavior of 18Ni(300) steel under solution-treated (ST) and solution-treated plus aged (STA) conditions, combined with characterization viaelectron backscatter diffraction (EBSD) and transmission electron microscopy (TEM), this study reveals that the synergistic effect of nonuniform martensite block size distribution and localized enrichment of geometrically necessary dislocations (GND) is the key mechanism exacerbating the Bauschinger effect. Research has demonstrated that homogenizing a material's microstructure and GND density through appropriate heat treatment protocols is an effective approach to mitigate the Bauschinger effect.