Korrosionsuntersuchung und quantitative Messung der Kristallitgröße von rührreibgeschweißten, hochfesten Aluminiumhybrid-Verbundwerkstoffen

This present study is centered on the corrosion behaviors and structural integrity of high strength aluminum-alloy 7075-T651 hybridized with carbonaceous coconut shell ash (CSA) and α+β titanium alloy powder in ratio of 50 : 50, fabricated during friction stir processing (FSP). The study examined the base metal – AA7075-T651 as well as the friction stir processed AA7075-T651 as control experiments. The Processing parameters used were plunge depth of 0.3 mm, travel speed of 20 mm/min, the tilt angle of 3° and rotational speed of 1500 min⁻¹. The corrosion characteristics were examined with the Potentiodynamic Polarization method in 3.5 % NaCl medium while crystalline phases were studied with x-ray diffraction (XRD). Results show that fabricated aluminum hybrid composite (AHC) AA7075-T651/coconut shell ash (CSA)/titanium-alloy has the highest percentage of inhibition performance efficiency (IPE) of 84.81 % resulting to 0.76938 mm/year corrosion rate and 356.51 Ω polarization resistance, whereas inhibition performance efficiency (IPE) for friction stir processed (FSPed) AA7075-T651 was 63.99 % while the base metal – AA7075-T651 was taken as the reference point. It was also revealed that the hybridized coconut shell ash (CSA)/titanium-alloy powder on AA7075-T651 enhanced the structural integrity, producing 38.5 nm crystallite size over friction stir processing (FSP) AA7075-T651 with 41.2 nm and the base metal with 48.7 nm crystallite size.