Alloy EN AW2011 is an aluminum alloy that belongs to the series of alloys 2XXX, where 5 - 6 wt.% Cu is added to aluminum. Alloys from this group, unlike other aluminum alloys, are poorly corrosion resistant, so they need to be protected by coatings or anodizing. The addition of copper significantly increases the strength of the material, so 2XXX series alloys are used in aerospace technology.
Different methods of heat treatment are known, the most common are solution annealing and aging. In the annealing process, the sample is heated to a certain temperature, and it is hold at the same temperature for a while, then it is cooled. Aging is a process in which particles are precipitated from solid solutions, which can greatly increase the strength properties.
The electrical resistance of aluminum is very low, as it is the material with the fourth lowest electric resistivity. Its specific electrical resistance is influenced by the amount and shape of the alloying elements and the impurities present in the microstructure. Aluminum alloys have a higher amount of alloying atoms, so they have a higher electrical resistivity than pure aluminum.
The purpose of bachelor thesis was to monitor the aging process of the EN AW2011 alloy by measuring the electrical resistivity. The alloy EN AW2011 was first homogenized, then artificially aged and the results were monitored through measurements of specific electrical resistivity. For the purpose of comparative analysis, 12-hour aging was performed at two temperatures, 150 ° C and 180 ° C. Afterwards, the DSC analysis was performed and the curves of the aging process as a function of time were created. Analyzing the curves, we can conclude that the basic aging process of the alloy EN AW2011 at 150 ºC takes place in the first seven hours, after which the curve is smoothed.
|
