The Effect of Pre- Stretching Treatment on the Microstructure, Mechanical Properties and Corrosion Resistance of 7075 Aluminum Alloy used in PEMFC

Among the various fuel cells, Proton Exchange Membrane Fuel Cells (PEMFC) offer many advantages, such as low temperature operation, quick starting, and high energy density. Therefore, the PEMFC can be extensively applied to power generation, portable electric equipment and hybrid vehicles. Heat treatable aluminum alloys such as 7075, because of high strength low density and corrosion resistance, are used widely in industry and PEMFC. In this industry, besides of mechanical properties, corrosion resistance is very important to work at that environment. T6 heat treatment has recommended for this regard, but this temper treatment is sensitive to corrosion induced and Stress Corrosion Cracking (SCC). In this work 5% Pre- Stretching after solution applied to this alloy in order to investigate its resistance to SCC. The results show that by this treatment, the precipitates immigrate from grain boundary into the grains inside and improve Stress Crack Corrosion (SCC) properties which is very important for using in PEMFC. Moreover, the results show that 5% Pre- Stretching after solution improves both tensile strength and elongation and 463MPa Tensile strength with 12% Elongation can be obtained by this heat treatment.