The Study Of Microstructure And Corrosion Behavior Of Aluminum/steel Clad Materials

Aluminum / steel composite material due to the corrosion of both aluminum and good mechanical properties of steel and other characteristics of more and more attention in practice.This article is based on industry,aluminum / steel composite material requirements for corrosion-resistant properties of the experiment.Given the state of today's experiment using metal layered composite materials research,there are some issues that this article for these key issues have been studied mainly involved in two aspects,one is to study the preparation process of the material,the material properties of one the study.In the preparation process,because the material used is cold-rolled and annealed prepared out,so cold rolling and annealing process of the main variables become the focus of this study.This paper studies the 4A60 / 08 Al and 4343 / 4A60 / 08 Al aluminum tissue / steel composite sheet and corrosion resistance of cold rolled and annealed condition,effects of different parameters on the microstructure and mechanical properties of materials and corrosion performance under different circumstances,for corrosion mechanism and strength of the material at different stages were analyzed and studied the characteristics of the material immersed corrosion,the main conclusions are as follows:(1)The amount of pressure under the influence of rolling,annealing temperature and time for steel substrate and aluminum cladding microstructure,you can see the amount of depression increases,internal material has a relatively large internal stress,grain It will be gradually stretched side.The higher the annealing temperature and the longer the holding time,will cause material recrystallization;however annealing temperature is too high and holding time is too long will make the final crystal is too large,it will reduce the strength of materials,plasticity and toughness;currently Wuxi Silver State selection The process parameters are: the amount of 60% under the pressure,annealing system 520 ? × 24 hrs,from the experimental results,it is reasonable production process;(2)Aluminum / steel bonding interface performs obvious elements diffusion phenomenon.Diffusion of aluminum to steel substrate steel faster than the rate of diffusion to the aluminum side,after transmission analysis,a relatively high concentration of oxygen content in the vicinity of the interface of aluminum and steel,and there exist FexAly brittle intermediate compounds,such compounds are relatively rigid,for General Properties of the material is relatively large,the actual production to try to avoid the appearance of such compounds;(3)The polarization curves are mainly tested at different concentrations of sodium chloride solution corrosion of materials alone.Experimental results show that 4A60 than 4343 more corrosion,mainly because 4343 material contains more Si element,easily and aluminum matrix material to form a very significant solid solution,these solid solution become entrained in the material matrix cathode phase,and materials aluminum body constituting the anode and cathode corrosion micro-cell,prompting corrosion occurs more easily;(4)The results show that the tensile stress corrosion material when it receives the dual role of stress and corrosive media,showing the fracture toughness.Crack dilute sulfuric acid material received promote hydrogen ion;dilute sodium hydroxide solution not only receive material erosion hydroxide example,while the aluminum cladding is sodium hydroxide dissolved severe,will reduce the material plastic;chlorine ions on crack initiation and propagation material has a very significant role,it will increase the sensitivity of crack promoting materials gradually become brittle;Corrosion of aluminum;aluminum corrosion:(5)using electrochemical noise corrosion monitoring material occurs in different environmental media,you can see the corrosion of materials remained the same,the corrosion of materials which can be divided into four stages;aluminum-electrical steel bimetallic galvanic corrosion;corrosion of steel substrate;In order to better improve the aluminum-steel interface binding capacity,avoid the diffusion annealing leads to brittleness Fex Aly compound,can participate in other elements in aluminum to suppress aluminum atom toward the iron matrix diffusion,it is a good can Considering improve the corrosion resistance of the material.