Influencing Intergranular Corrosion via Surface Treatment

The amount of aluminum used in cars by the automotive industry has doubled during the last 10 years. Further growth is expected for the following years. Especially 6xxx aluminum alloys, which have the potential to make cars lighter and more economical. The consequential growing demand for high quality aluminum extrusions could be constrained by the problem of intergranular corrosion. The demand for intergranular corrosion resistant aluminum parts is an important issue for the aluminum industry. TRIMET has evaluated a method, which is used for increasing the corrosion resistance of steel. Shot peening is in use for corrosion prevention of steel parts. The prevention mechanism is the introduction of near surface compressive stresses. Additionally some papers also report positive effects of shot peening on the corrosion resistance of aluminum parts. The paper describes the corrosion testing of surface and heat treated aluminum profiles and presents the results concerning corrosion and applicability.