Division of Marine System Engineering, Mokpo Maritime University, Mokpo, Jeonnam, 58628, Korea.
J Nanosci Nanotechnol. 2019 Jul 1;19(7):4265-4269. doi: 10.1166/jnn.2019.16270.
This study investigated influence of sensitization on the mechanical properties of AISI 304 stainless steel. The small and tensile specimens were isothermally aged at 650 °C for up to 1000 hours. Microstructure and precipitates of these specimens were characterized by scanning electrode microscope with energy dispersive X-ray spectroscopy. The degree of sensitization of aged specimens was measured by double loop electrochemical potentiodynamic reactivation method. The tensile test was conducted to evaluate mechanical properties of these specimens. With the progress of aging, the degree of sensitization value drastically increased to more than 50% as Cr-rich carbides were precipitated in the austenite grain boundaries. Also, the mechanical properties were degraded, and fracture mode drastically changed from ductile to brittle. As a result, the surface damage and degradation of mechanical properties were correlated with the degree of sensitization value.
本研究探讨了敏化对 AISI 304 不锈钢力学性能的影响。小拉伸试样在 650°C 下进行等温时效处理，时间长达 1000 小时。通过扫描电子显微镜和能谱分析对这些试样的微观结构和析出物进行了表征。采用双环电化学动电位再活化法测量了时效试样的敏化程度。通过拉伸试验评估了这些试样的力学性能。随着时效的进行，Cr 富碳化物在奥氏体晶界析出，敏化度值急剧增加到 50%以上。同时，力学性能下降，断裂模式从韧性变为脆性。结果表明，表面损伤和力学性能的退化与敏化度值有关。
