International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This paper investigates the influence of aging parameters (temperature and time) on thermal, mechanical and structural properties of the EN AW-6060 aluminum alloy. Thermal diffusivity and hardness were measured after applied heat treatments followed by investigation on scanning electron and transmission electron microscopes. Heat treatments included: solutionizing at 550°C for 1 hour followed by quenching in ice water; after quenching samples were aged at two separate temperatures of 180°C and 200°C for 1-8 hours. The results show that hardness gradually increases with aging time achieving peak value of 95 HV10 after aging at 180°C for 5 hours. Thermal
diffusivity also increases with both aging time and temperature achieving peak values after aging at 200°C for 4 hours. SEM/EDS analysis show the existence of finely distributed precipitates containing Mg, Si and Fe. TEM investigation confirms the existence of rod-shaped precipitates several nanometers in length.

The aim of this paper is the investigation of the effect of natural aging on the mechanical, physical and microstructural properties of an EN AW-6060 aluminum alloy. These properties were investigated during different aging treatments. Firstly, the effect of natural aging on properties was investigated, after which the influence of natural aging (room temperature pre-aging) on the artificial aging was studied. The results showed the beneficial effect of natural aging in both sets of experiment. During the natural aging, the hardness increased for around 20 % while electrical conductivity values were slightly higher than in the quenched sample. The hardness of the samples gradually increases up to 25 days of natural aging reaching a plateau state, after which the values of hardness remain the same. Also, room temperature pre-aging had a positive effect on subsequent artificial aging. Samples that were pre-aged for 40 days or more before artificial aging had around a 13 % increase in hardness values compared to the samples that were directly artificially aged. Electrical conductivity had increased by around 1 MS/m in pre-aged samples compared to only artificially aged samples. Optical microscopy investigations confirmed the existence of precipitated phases and their distribution in the microstructure.