Regensburg 2025 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 36: Mechanical Properties

MM 36.1: Talk

Friday, March 21, 2025, 10:15–10:30, H23

STEM investigation of early precipitation reactions in Al-Cu alloys — •Johannes Berlin and Ferdinand Haider — Chair for Experimental Physics I, University of Augsburg, Universitätsstraße 1, 86159 Augsbur

Due to their excellent strength-to-weight ratio, heat-treatable Al-Cu alloys have been widely used since their invention. Although the occurring precipitates in naturally aging aluminium alloys are well known, the very early stages of formation mechanisms still are a topic of ongoing research. Scanning transmission electron microscopy is used to investigate the influence of different parameters, such as thermal history and effects of microalloying, on early-stage precipitate formation and transformation in Al. Due to their strong binding potential to quenched in vacancies even a few hundred ppm of trace elements such as tin and indium can alter the natural aging process drastically. Even after prolonged natural ageing, a slight increase in temperature can lead to drastic changes in precipitation size and densitiy inthese materials. This proves a long-lasting supersaturation of the material with vacancies. Additionally, these results are compared to the measurements of hardness, DSC and electrical resistance.

Keywords: Aluminium; alloy; STEM