Aluminium alloys are among the most important lightweight materials due to their low density, good specific strength, and corrosion resistance. However, most commercial aluminium alloys do not provide sufficient microstructural stability at operating temperatures above 130 °C. This doctoral research adopts a holistic approach. It first addresses thermodynamic calculations and casting simulations. Based on these results, a permanent mould ensuring a selected cooling rate was designed, followed by alloy synthesis and casting. An aluminium alloy from the Al-Ni system with a eutectic chemical composition was alloyed with zirconium (0.2–0.6 wt.%) and subjected to T5 artificial aging heat treatment. Microstructural analyses, microhardness measurements, and electrical conductivity measurements were performed on the castings. Analytical results, confirmed by statistical analysis of variance, identified the optimal chemical composition and heat treatment, represented by the alloy AlNi6.1Zr0.6 wt.% aged for 48 h at 350 °C. For mechanical characterisation, tensile tests were carried out at room temperature, 250 °C, and 300 °C, followed by accelerated compressive creep tests. In addition, microstructural stability after long-term aging for two months at 350 °C was analysed. The analyses demonstrated good thermal stability of the eutectic (αAl + Al3Ni) and L12-Al3Zr precipitates. The research establishes a correlation between chemical composition, heat treatment, microstructure, and mechanical properties, and contributes to the development of new aluminium alloys with improved thermal stability above 250 °C.
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