The diploma thesis focuses on the thermodynamic characterization of the EN AW-6082 aluminium alloy with different additions of lanthanum. The EN AW-6082 alloy belongs to the group of 6XXX series wrought aluminium alloys, which are characterized by the Al–Mg–Si alloying system. These alloys exhibit a favourable combination of mechanical properties, corrosion resistance, weldability, and processability, making them suitable for a wide range of industrial applications.
The research was conducted by comparing a reference alloy without lanthanum addition with two alloys containing 0.1 wt. and 0.2 wt. % La, respectively. Various characterization methods, including simple thermal analysis (ETA), differential scanning calorimetry (DSC), optical microscopy, scanning electron microscopy (SEM), and thermodynamic calculations, were used to analyse the solidification behaviour, phase equilibria, and microstructure. The obtained results were subsequently compared between the investigated alloys to determine the extent of the influence of lanthanum addition.
The thermal analysis and DSC results showed that the overall solidification range remained largely unchanged with the addition of lanthanum. The addition of lanthanum to the EN AW-6082 alloy resulted only in a slight increase of the liquidus temperature. Thermodynamic calculations indicate that lanthanum becomes incorporated into La-containing intermetallic phases already during the early stages of solidification. Their presence is also reflected when using optical and scanning electron microscopy, where the AlLaSi phase was observed in the alloys containing lanthanum, alongside other intermetallic phases.
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