Chrom als Mikrolegierungselement - Einfluss auf das Rekristallisationsverhalten der Aluminiumlegierung 2024

Research output: ThesisMaster's Thesis

Abstract

In this master thesis the influence of chromium as a micro-alloying element on the recrystallization behaviour of the aluminium-copper-alloy 2024 was investigated. Due to the low corrosion resistance, the alloy is cladded on both sides with pure aluminium. The aim of this thesis was to find a solution to suppress grain coarsening which appears after a critical deformation and which degrades the mechanical properties. Moreover, the orange-peel-effect, caused by the coarse grain, must not occur since the alloy is often used as outer skin in aeroplanes. Stretching experiments and subsequent solution annealing were realised with chromium and non-chromium containing alloy variants. It was shown that after solution annealing the material is fully recrystallized. Special attention was paid to the change of the size, amount and shape of the precipitates. The mechanical properties were determined by tensile testing and the microstructure was characterized by light-optical microscopy, high-resolution scanning electron microscopy and transmission electron microscopy. In summary, it can be stated that the impact of chromium as a micro alloying element results in a higher percentage of Al20Cu2Mn3 precipitates. Due to this, the movement of grain boundaries is hindered effectively. In addition, start of recrystallization is delayed, the final grain size is smaller and the mechanical properties are improved.

Details

Translated title of the contributionChromium as micro alloying element – influence on the recrystallization behaviour of the aluminium alloy 2024
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
Award date26 Jun 2015
Publication statusPublished - 2015