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MM: Fachverband Metall- und Materialphysik

MM 29: Poster II

MM 29.13: Poster

Tuesday, March 19, 2024, 17:00–19:00, Poster B

Reversion experiments for Guinier-Preston zones in Al-Cu — Max Obermair, •Hamideh Dorri, Johannes Berlin, and Ferdinand Haider — Chair for Experimental Physics I, University of Augsburg, Universitätsstraße 1, 86159 Augsburg

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. Loss of hardness during an increase in temperature to about 100°C after prolonged natural aging indicates a dissolution of the GP zones. Using hardness measurements, differential calorimetry and in-situ resistometry we were able to show, that this dissolution is still controlled by excess vacancies and that the formation of GP-2 zones depends on the thermal history of the samples.

Keywords: Aluminium; Guinier-Preston Zones; Precipitates; Vacancies; Resistometry