High-throughput characterisation of the long-term ageing of an A357+1wt%Cu cast aluminium alloy using temperature gradient

A357 alloy is a widely studied cast aluminium alloy used in applications such as cylinder heads or aerospace applications. The addition of 1wt% copper to this alloy modifies the nanometric precipitation sequence and improves heat resistance. Thermal ageing resistance is a critical property for such applications and the ability to predict the end of life of these products is crucial. In this study, we investigate the effect of long-term ageing on an A357+1wt%Cu alloy. We have developed a combinatorial approach to gather sufficient data to model the evolution of mechanical properties during extended ageing. Samples have been aged in a temperature gradient for durations up to 10,000 h and then characterised using space-resolved Small- and Wide-Angle X-ray Scattering (SAXS & WAXS), as well as hardness mapping. Complementary Transmission Electron Microscopy (TEM) observations were also performed. Finally, a simple approach based on time-temperature equivalence is implemented to predict the evolution of the mechanical properties and the nanometric precipitation during long-term ageing.