| dc.description.abstract | New models for modeling the material properties for aluminium alloys that can take into
consideration the geometry of the needle shaped precipitates, that can be found in 6xxx
alloys are being developed. The background for this thesis is to help find needed experimental
data to calibrate and develop these model further. In this thesis the chosen material
to study was from an extruded plate of AA6082 aluminium, which is a relevant material
in for example the automobile industry.
Three different tempered cases has been studied in depth with Transmission Electron
Microscopy, tensile tests and hardness curves. A hardness curve was made to find T6
which is the first case. The second case was weakly over aged at 185 ◦C after reaching
T6 until it reached ≈ 70% of peak hardness. The third case was over aged at 200 ◦C
after reaching T6 until it also reached ≈ 70% peak hardness. It has been made cross
section area and length distributions of the precipitates for the three cases using a TEM.
The tensile tests were done to relate the contributions of the different particle parameters
such as length, cross section area and density to the mechanical properties of the material.
It was found in the tensile tests that the over aged materials experienced increased
initial work hardening rate as compared to T6. The distributions showed that the material
over aged at 200 ◦C had wider and shorter precipitates compared to the material over aged
at 185 ◦C. It was also found that the over aged materials has a significantly lower particle
density compared to T6. | |
