This study aims to determine the effect of milling time and sintering temperature parameters on the alumina transformation phase in the manufacture of Aluminium Matrix Composites (AMCs) reinforced by 20 % silica sand tailings using powder metallurgy technology. The matrix and fillers use waste to make the composites more efficient, clean the environment, and increase waste utilization. The milling time applied to the Mechanical Alloying (MA) process was 0.5, 6, 24, 48, and 96 hours, with a ball parameter ratio of 15:1 and a rotation of 93 rpm. Furthermore, hot compaction was carried out using a 100 MPa two-way hydraulic compression machine at a temperature of 300 °C for 20 minutes. The temperature variables of the sintering parameter process were 550, 600 to 650 °C, with a holding time of 10 minutes. Characterization of materials carried out included testing particle size, porosity, X-Ray Diffraction (XRD), SEM-Image, and SEM-EDX. The particle measurement of mechanical alloying processed, using Particle Size Analyzer (PSA) instrument and based on XRD data using the Scherrer equation, showed a relatively similar trend, decreasing particle size occurs when milling time was increased 0.5 to 24 hours. However, when the milling time increases to 48 and 96 hours, the particle size tends to increase slightly, due to cold-weld and agglomeration when the Mechanical Alloying is processed. The impact is the occurrence of the matrix and filler particle pairs in the cold-weld state. So, the results of XRD and SEM-EDX characterization showed a second phase transformation to form alumina compounds at a relatively low sintering temperature of 600 °C after the mechanical alloying process was carried out with a milling time on least 24 hours

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Due to the increased demand for aluminium and the prohibitive cost of producing primary aluminium, the process of making AMCs using recycled aluminium alloy as a matrix and silica sand tailing without leaching as a filler is essential to be developed. For more cost-effective, the purpose of this study is to make particulate aluminium composite matrix AMCs with a matrix of recycled aluminium and reinforced with silica sand tailing without leaching. This research involves the effect of differences in grain size and filler weight percentage on matrix Al-ZnSiFeCuMg recycled aluminium alloy powder. This study used powder metallurgy technology as well as two-way hot-compaction (300°C) and applied a sintering temperature of 550°C. Density, hardness, and wear testing, as well as microstructure analysis, were conducted to determine the characteristics of the resulting AMCs. An increase in hardness of 67% was achieved by the AMCs-164 µm-20%SiO2 specimen, which used a filler grain size of 164 µm wt.20%. Meanwhile, AMCs-31 µm-20%SiO2, which used a filler grain size of 31 µm, only increased by 63%. The wear test result also showed a lower wear rate achieved by the AMCs-164 µm-20%SiO2 specimen. The results analyses using SEM-EDS instruments showed higher agglomeration and porosity in specimens using a filler grain size of 31 µm, while AMCs using a filler grain size of 164 µm showed an even spread of filler powder. Therefore, AMCs that used 164 µm powder-sized fillers have a stronger bond between the filler and the matrix and produce AMCs that are harder than AMCs that use 31 µm fillers.