Effect of multiwalled carbon nanotubes on elevated temperature tensile and wear behavior of Al2024 matrix composites fabricated by stir casting and hot extrusion

Abstract

In this study, aluminum alloy matrix composites reinforced with MWCNT particles by 0.5 wt.% were fabricated by a new developed technique, consisting of semi-powder metallurgy and stir casting processes. Then, hot extrusion process was applied to the composite materials. Phase analysis and microstructure investigations were performed for the as-cast and extruded samples. Hardness test was conducted, and tensile tests were applied at room, 150 and 250 degrees C. The tribological performances of unreinforced alloy and MWCNT-reinforced composite were examined at room, 150 and 250 degrees C as well. The results showed that hardness of base aluminum alloy was improved. The peaks belonging to the MWCNT were detected by x-ray diffraction (XRD) analysis. The incorporation of MWCNT presents strengthening effect on the mechanical properties at all test temperatures. The wear rate generally decreased with the addition of MWCNT for all test conditions. Extrusion process had a positive effect to enhance wear and hardness behavior. Abrasive, adhesive, oxidative and thermal wear mechanisms were observed by scanning electron microscope.