Influence of Mo content on the phase evolution and corrosion behavior of model Fe–9Cr–xMo (x = 5, 7, and 9 wt%) alloys

• Published in: Journal of materials research 2015-06, Vol.30 (12), p.1999-2007
• Main Authors: Gomes da Silva, Marcelo J., Herculano, Luis F.G., Urcezino, Amanda S.C., Araújo, Walney S., de Abreu, Hamilton F.G., de Lima-Neto, Pedro
• Format: Article
• Language: English
• Subjects: Alloys; Analysis; Annealing; Applied and Technical Physics; Biomaterials; Chromium; Chromium molybdenum steels; Corrosion; Corrosion resistance; Corrosion tests; Electrodes; Evolution; Ferrous alloys; Heat treatment; Hot rolling; Inorganic Chemistry; Materials Engineering; Materials research; Materials Science; Molybdenum; Nanotechnology; Phase transitions; Software; Studies; Temperature
• ISSN: 0884-2914; 2044-5326
• DOI: 10.1557/jmr.2015.157

Model Fe–9Cr–xMo alloys with high Mo content alloys were cast to investigate the effect of Mo on the phase evolution and properties of the alloys. The Mo contents in the alloys were 5, 7, and 9 wt%, while the Cr content was held constant at 9 wt%. For comparison, a commercial A213T 9-P9 (Fe–9Cr–1Mo) alloy, widely used in the petrochemical industry, was also investigated. The alloys were heat-treated at temperatures between 450 and 650 °C and characterized by scanning electron microscopy, x-ray dispersive energy spectroscopy, and electron backscatter diffraction. Potentiodynamic linear polarization technique was used to evaluate the corrosion of the alloys in a 0.5 mol L−1 H2SO4 solution containing 0.1 mol L−1 NaCl. The results showed that the corrosion resistance of the alloys was affected by precipitation of the µ phase and that the Mo content in excess of 5% is deleterious to the corrosion resistance of the Fe–Cr–Mo alloys.