Martensitic transformation in an intergranular corrosion area of austenitic stainless steel during thermal cycling

• Published in: Corrosion science Vol. 85; pp. 1 - 6
• Main Authors: La Fontaine, Alexandre, Yen, Hung-Wei, Trimby, Patrick, Moody, Steven, Miller, Sarah, Chensee, Martin, Ringer, Simon, Cairney, Julie
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.08.2014; Elsevier
• Subjects: A. Stainless steel; Applied sciences; B. SEM; B. TEM; B. Thermal cycling; C. High temperature corrosion; C. Intergranular corrosion; Corrosion; Corrosion environments; Exact sciences and technology; Metals. Metallurgy; B. SEM; C. High temperature corrosion; B. Thermal cycling; C. Intergranular corrosion; A. Stainless steel; B. TEM; Austenitic stainless steel; Scanning electron microscopy; Temperature; Thermal cycle; High temperature; Intergranular corrosion; Phase transformation; Transmission electron microscopy; Austenitic steel; Stainless steel; Martensitic transformation; High temperature corrosion
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2014.04.048

An oxidation-assisted martensitic phase transformation was observed in an austenitic stainless steel after thermal cycling up to 970°C in air in a solar thermal steam reformer. The intergranular corrosion areas were investigated by electron backscatter diffraction (EBSD), transmission Kikuchi diffraction (TKD) and transmission electron microscopy (TEM). The structural-and-chemical maps revealed that within intergranular corrosion areas this martensitic transformation primarily occurs in oxidation-induced chromium-depleted zones, rather than due to only sensitization. This displacive transformation may also play a significant role in the rate at which intergranular corrosion takes place.