Abstract

Super duplex stainless steel specimens were subjected to controlled (in a deformation simulator) thermal and thermal plus deformation treatments. The objective was to relate the corrosion performance with hot (1000-1300°C) deformed microstructures. The microstructural evolutions were quantified with extensive microtextural characterization and measurements of phase-specific micro-hardness. The corrosion behavior was investigated by anodic polarization and phase-specific selective dissolution methods. Though the thermal treatment imposed an increasing degradation in corrosion performance with holding temperature, the associated deformation at that temperature brought a non-monotonic behavior. The best corrosion performance (or the lowest passivation current density) was noted in the specimen deformed at ~1100°C. This superior corrosion behavior was attributed to the grain size refinement in the austenite phase. Finally, a combination of transmission Kikuchi diffraction (TKD) plus transmission electron microscopy (TEM) clearly related the grain size refinement to discontinuous dynamic recrystallization. The overall corrosion behavior was shown to be determined by a balance between decreasing austenite fraction and dynamic recrystallization-induced grain size refinement of the austenite phase.

Graphical Abstract

中文翻译：

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超级双相不锈钢的动态再结晶和特定相腐蚀性能

摘要

超级双相不锈钢试样经过受控（在变形模拟器中）热和热加变形处理。目的是将腐蚀性能与热 (1000-1300°C) 变形微观结构联系起来。微观结构演变通过广泛的微观结构表征和特定相显微硬度的测量进行量化。通过阳极极化和特定相选择性溶解方法研究腐蚀行为。尽管热处理导致腐蚀性能随保温温度的降低而增加，但在该温度下相关的变形带来了非单调行为。在约 1100°C 变形的样品中注意到最佳的腐蚀性能（或最低的钝化电流密度）。这种优越的腐蚀行为归因于奥氏体相中晶粒尺寸的细化。最后，透射菊池衍射 (TKD) 和透射电子显微镜 (TEM) 的组合清楚地将晶粒尺寸细化与不连续动态再结晶联系起来。显示整体腐蚀行为由降低的奥氏体分数和动态再结晶诱导的奥氏体相晶粒尺寸细化之间的平衡决定。

图形概要