Fabrication of Al7075-MWCNT Composite Powder by Recycling Aluminum Alloy Chips Via High Energy Milling and Alloying

In this study, aluminum chips were milled in a planetary ball mill at different times and ball-to-powder weight ratios (BPRs). The resulting optimum powder was reinforced with 1 wt% and 2 wt% of multi-walled carbon nanotubes (MWCNTs). The effects of alloying time, BPR, and MWCNTs percentage on the morphology, distribution, and composition of the Al7075-MWCNT powder were investigated. The results showed that smaller particles with a limited size distribution can be obtainable by increasing BPR and decreasing mechanical milling time. A uniform dispersion of reinforcement (2 wt%) was achieved at lower alloying times (15 and 30 min) and a higher BPR (20:1). Using XRD analysis, it was revealed that the carbon peaks are more clearly in 2%-MWCNT powders than 1%-MWCNT ones. The addition of MWCNTs led to reducing the particle size; this is confirmed by the data obtained from the XRD patterns and their analysis with the Williamson-Hall model. Machining chips were converted into composite powder by cost-effective mechanical milling and alloying method with a uniform distribution of MWCNTs, which is unique.