The microstructure evolution and the pitting corrosion resistance of a supermartensitic stainless steel after deep cryogenic treatment process were clarified through X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy (TEM) and electrochemical methods. The results showed that the microstructure of supermartensitic stainless steel mainly consisted of reversed austenite, tempered martensite, and M₂₃C₆ carbides after tempering. The deep cryogenic treatment promoted the refinement of the martensite laths and the precipitation of the carbides in comparison with the traditional process. TEM analysis indicated that the segregation of Si atoms at the boundary was found at the interface between carbide and martensite. The pitting corrosion potential of the specimens subjected to deep cryogenic treatment decreased with the elevated tempering temperature, and the lowest pitting corrosion potential was found at the tempering temperature of 650 °C. The sensitivity of the pitting corrosion potential was attributed to the precipitation of M₂₃C₆ carbides and Si atoms segregation. Si atoms segregation engendered the formation of Cr-depleted zone near M₂₃C₆ and impeded the recovery of Cr-depleted zone.

通过X射线衍射，场发射扫描电子显微镜，透射电子显微镜（TEM）和电化学方法，对深冷处理后的超马氏体不锈钢进行了显微组织演变和抗点蚀性能的研究。结果表明，超马氏体不锈钢的显微组织主要由反向奥氏体，回火马氏体和M ₂₃ C _6组成。回火后的碳化物。与传统工艺相比，深低温处理促进了马氏体板条的细化和碳化物的析出。TEM分析表明，在碳化物与马氏体之间的界面处发现了Si原子的偏析。随着回火温度的升高，经过深低温处理的试样的点腐蚀电位降低，在650℃的回火温度下发现最低的点腐蚀电位。点蚀电位的敏感性归因于M ₂₃ C ₆碳化物的析出和Si原子的偏析。硅原子的偏析促使M ₂₃ C ₆附近形成Cr贫化区 并阻碍了Cr耗尽区的恢复。