Duplex Corrosion Mechanisms Correlated to Α/γ Phase Selection in Containerlessly Processed Fe-Cr-Ni-Mo Alloy

The & alpha;/& gamma; phase selection mechanism and corrosion resistance of Fe-21%Cr-12%Ni-5%Mo alloy were investigated by both individual electromagnetic levitation (EML) and EML coupled with falling quench (EML+FQ) techniques. The decomposition of primary & delta; phase could be partially or completely suppressed in two containerless processing. Both selective and pitting corrosion behaviors were discovered in alloy, which were related to the crystalline orientations and solute distributions of constituent phases. The anti-corrosion property of EML+FQ processed alloy was significantly enhanced with higher corrosion potential of 0 VSCE, lower corrosion current density of 4.1 x 10-7 A/cm2 and lower corrosion rate decreasing over one order of magnitude.