ABSTRACT
The main focus of this study is the microstructure changes of aluminum 6061 after natural and artificial aging. Aluminum 6061 has been aged naturally in room temperature for 7 days before aged artificially. Artificial aging has been conducted at a temperature of 200°C, withholding time variations of 2, 4, and 6 hours. According to the microstructure test, the grain size of aluminum 6061 got smaller after artificial aging for 4 hours, and then it got bigger after artificial aging for 6 hours. The study result showed that the best outcome was artificial for 4 hours after natural aging. This result was in line with the hardness test result, where the highest hardness number was obtained in specimens with artificial aging treatment for 4 hours after natural aging with a hardness number of 106.8 HRE. The increasing hardness was thought to be due to the formation of Mg2Si precipitates.
