Long‐Term Corrosion Behavior Study of Aluminum‐Alloy/Stainless‐Steel Inertia Friction–Welded Tank Storing N₂O₄

Abstract

In this work, the materials from different positions of 2219 aluminum alloy/304 stainless steel inertia friction welded tank with long‐term storage of N2O4 were studied. The results showed that the corrosion product layer composed of Fe3O4 and FeCr2O4 was covered on the surface of stainless steel. The corrosion product layer on the surface of stainless steel can effectively improve the protection effect. Severe corrosion occurred in both the sidewall and bottom aluminum alloy, with intergranular corrosion depths of about 30 to 50μm observed in the cross‐section, accompanied by typical exfoliation corrosion. A Fe‐Al dominated intermetallic compound layer was formed at the weld. A dynamic recrystallization zone and thermo‐mechnical affected zone were included on the aluminum alloy side with intergranular corrosion depths of 4.3 and 13.3μm, respectively. The granular Al matrix can be seen on the peeling surface of the aluminum alloy. Combining scanning Kelvin probe and potentiodynamic polarization curve results, the high potential of the stainless steel could further promote the corrosion of the aluminum alloy.This article is protected by copyright. All rights reserved.