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1. According to XRD examination, the widening of the diffraction pattern could very well be attributable to the increase in the duration of milling from 0 to 20 hours, showing that perhaps the nano-crystalline state had been established as a result of HEBM. The emergence of MgZn2 precipitates due to the combined application of heat and pressure was validated by XRD examination.
2. The relative density was inversely proportional to the increase in milling time which reduced the particle size from 0 to 49 nm after 20 h of milling of the base powders.
3. Owing to the precipitation hardening phenomena, the microhardness of all the specimens steadily enhanced after 3, 6, 12, and 24 hours of artificial ageing at 115°C. Peakage hardness was attained at 24 h of ageing, beyond which the microhardness (VHN) of all the specimens, regardless of particle size, began to decline. Overageing occurred after 96 h of ageing.
4. When compared to the other specimens, the T6 treated Al 7150 alloy made of milled powders of 49 nm size showed a superior microhardness of 255 VHN. This is due to the particle size reduction due to increasing the duration of milling as well as close packing of the powders under the influence of the simultaneous application of pressure and heat during hot pressing.
5. Pin on disc wear testing conducted under varying loads and sliding speeds showed the beneficial effect of artificial ageing in enhancing the wear behavior of the T6 treated samples.
6. The capacity of the T6 specimens to withstand the dry sliding wear loads throughout pin-on-disc wear testing can be attributed to the development of (MgZn2) precipitates, which slowed dislocation movements.
7. The T6 sample’s HRTEM microstructure showed a high density of MgZn2 precipitates dispersed evenly in the Al 7150 alloy matrix, the precipitates comprising of the metastable η′ phase, with lesser amounts of GP zones and the stable η phase were observed.
8. FESEM morphology revealed extensive damage on the wear specimen’s surface due to severe plastic deformation during wear testing, indicating poor wear resistance of the non-aged samples. A mixture of adhesive, delamination and abrasive wear modes was identified during FESEM analysis.
9. The current study concludes that by optimizing the process parameters such as milling time, ageing as well as reducing the particle size of the base powders, the hardness and wear behavior of Al 7150 alloy may be improved.