Recycling aluminium (Al 6061) chip through powder metallurgy route

The Al 6061 was recycled by using the powder metallurgy technique to determine the effect of particle size distribution on mechanical and microstructure of materials. Analysis of the microstructure, green density and microhardness was conducted to test the performance of recycled aluminium. The project was conducted by using Al 6061 with the addition of 4% of alumina (3–4 μm). The results showed that green density of Al 6061 was lower than pure Al 6061. As the speed of ball mill increases from 100, 150 and 200 rev min−1, the green density increases. Next, the samples were sintered at 500, 550 and 600°C. Microstructure of 100 rev min−1 samples having the lowest green density shows larger and more frequent porosity compared to higher green density samples with smaller and less visible porosity. The sample with 200 rev min−1 ball mill speed showed the highest Vickers hardness value followed by 150 and 100 rev min−1 in the range from approximately 60–150 Hv.