Analyses of Fatigue Resistance of Recycled AA 6061 by Hot Extrusion Using ANOVA Method
This study focuses on analyzing the fatigue life recovery in solid-state recycled (direct recycling without remelting) aluminium AA 6061 processed via the hot extrusion operation. The analyses were achieved by varying the factors of preheating temperature (PHT) at 450, 500 and 5500C and preheating time (PHti) at 1, 2, and 3 hours respectively. The effect of these parameters was analyzed on the fatigue of the produced alloy using the ANOVA technique in addition to the full factorial design with 2 replicates and 3 center points. From the result, it is indicated that the PHT parameter is more significant to be controlled rather than the PHti. An increase of PHT produced higher fatigue resistance. Among the selected parameters, extrudates show the best fatigue resistance at 550 °C and for 3 hours preheating. The analyses revealed that PHT was the main key parameter that takes control of the fatigue resistance in the recycling of the AA 6061 chip. Analysis of optical micrographs of the extrudates was also illustrated and discussed.