Regensburg 2025 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 9: Poster

MM 9.29: Poster

Montag, 17. März 2025, 18:30–20:30, P1

Role of trace elements on the GP-Zone formation Al-Cu alloys — •Sandra Müller, Isidor Switalla, Johannes Berlin, and Ferdinand Haider — Chair for Experimental Physics I, University of Augsburg, Universitätsstraße 1, 86159 Augsbur

Both formation and dissolution of Guinier-Preston zones in Al-Cu alloys depend on the presence of excess vacancies. They are quenched in from the high temperature homogenisation treatment but will possibly disappear during the natural aging at ambient temperature. The lifetime of excess vacancies in pure Aluminium is much shorter than that in Al-Cu alloys, where vacancies presumably are trapped in GP zones. Therefore, a small increase in temperature can lead to drastic changes in the microstructure of these materials by releasing the trapped vacancies. Resistometry is a simple online method to monitor changes in the microstructure of a metallic alloy, complemented by DSC and hardness measurement.In this work we focused on natural and slightly above room temperature artificial ageing of Al-Cu samples containing 2 - 4 wt.% of Cu. DSC gives rather clear evidence that precursor cluster of only very few atoms form before the GP-zones are detected. Those precursors and the GP zones formation can be suppressed or delayed by minor addition of vacancy-binding trace elements like Tin and Indium.

Keywords: Aluminium; alloy; DSC; Resistivity