Effect of process parameters on corrosion rate of friction stir welded aluminium SiC–Gr hybrid composites

Abstract

In the present study, the influence of processing parameters of friction stir welding on the corrosion rate of the welded joints of aluminium SiC–Gr hybrid composites was investigated. The experimental results indicate that the corrosion resistance of the welded joints increases at high welding (traverse) speed and/or low values of rotational speed. These variations occur as a result of the changes in the joint microstructure, where fine grains are developed as a consequence of a relatively low heat input and fast cooling to room temperature by ambient air associated with low rotational speed and/or high welding speeds. The mixed electrode theory is used to explain these variations of the corrosion rate, where the area ratio of cathode/anode for the galvanic couple between the aluminium metal matrix and the reinforcement constituents becomes small for fine grains. Thus, the corrosion resistance of the welded joints is increased.

Keywords:

• Hybrid composite
• Friction stir welding
• Corrosion

This work was supported by a grant from the Deanship of Scientific Research at Jordan University of Science and Technology (grant no. 2010/195). The authors also would like to acknowledge all members of the Industrial Engineering Department workshops and laboratories for their help in using the machines and other available facilities.