Corrosion Analysis of Rapidly Solidified and Subsequently Aged Al‐Ni and Al‐Fe‐Ni Alloys

ABSTRACT This study investigates the influence of Fe addition and heat treatment on the corrosion behavior of Al–5 wt.%Ni and Al–2 wt.%Fe–1.5 wt.%Ni alloys, with particular emphasis on the role of intermetallic phase chemistry and distribution. Microstructural analysis reveals that the binary alloy is characterized by the presence of Al 3 Ni intermetallics, while the ternary alloy promotes the formation of Fe‐containing phases such as Al 9 FeNi and Al 3 (Fe,Ni), resulting in a redistribution of Ni within the microstructure. Electrochemical impedance measurements indicate that the ternary alloy exhibits higher charge‐transfer resistance than the binary counterpart; however, this increase does not correspond systematically to lower corrosion current densities or improved overall corrosion resistance. The results indicate a transition in corrosion mode: the binary alloy exhibits more generalized corrosion over larger surface areas, whereas the ternary alloy exhibits more spatially heterogeneous and preferential attack associated with the intermetallic phases. Fe addition does not intrinsically improve corrosion resistance but alters intermetallic chemistry and electrochemical contrast, reducing the extent of widespread galvanic dissolution.