Fabrication and Corrosion Properties of Iron Aluminum Alloy/Steel Laminated Composite Prepared by Clad Rolling

摘要

The laminated composite of Fe-Al alloy and CrMo steel was fabricated by clad rolling to provide additional properties to the steel such as corrosion resistance, strength, and light weight. Three layered composite consisting of alloy/steel/alloy was succesfully fabricated using the process condition to satisfy the criteria for simultaneous deformation of different materials. The fabricated composite could be cold rolled to 120 μm thickness (99.8 % reduction), and wound to a coil without damage. The corrosion resistance of the composite in a sulfuric acid solution was comparable to that of monolithic CrMo steel, and it depends on the aluminium content of the Fe-Al alloy. The aluminium content dependence of the corrosion behavior is explained by the corrosion potential (E_(corr)) of the Fe-Al alloy derived from the polarization curves in the solution. In order to improve the corrosion resistance of the composite, pre-oxidation treatment was conducted to form Al_2O_3 layer to protect the substrate. Analyses by XPS and SIMS show that the Al_2O_3 oxide fraction increases with the oxidization temperature and Al content of the alloy. The pre-oxidation treatment improved the corrosion resistance of the composite in a sulfuric acid solution. It is concluded that the effect of oxidation on the corrosion resistance is due to the formation of Al_2O_3 oxide and the Al_2O_3 fraction in the oxides.