Entwicklung einer hochfesten, gut verformbaren 6xxx-Automobillegierung

Translated title of the contribution: Development of a high strength, good formable 6xxx automotive alloy

Marcel Christian Grömer

Research output: ThesisMaster's Thesis

Abstract

6xxx aluminium alloys are well suited for use in automotive industry due to their good formability and high strength. Currently, alloys such as EN-AW 6016 and AA 6111 are mainly used, but since the tireless increase of requirements, there is a high demand for optimized 6xxx alloys even within these composition boundaries. Industrial production of AlMgSi-sheet material starts with continuous casting followed by homogenisation treatment and rolling process. After that, a solution treatment is applied as 6xxx alloys are among age-hardenable. In this process a supersaturated solution is formed, which can be used to eventually increase the in-service strength during the final paint-bake treatment by the formation of nano-metre sized precipitates. The aim of this thesis is the development of an optimized 6xxx alloy which shows high in-service strength as well as a good formability in T4 and a sufficient high bendability in T64 after a paint-bake simulation. First, thermodynamic simulations are performed to identify potential alloys. In this context, three base compositions were found: alloys with an excess amount of silicon, alloys with an excess amount of magnesium and alloys with equal amounts of Mg and Si. Further elements like Cu, Mn or Cr were added to investigate their impact on the mechanical behaviour. Sheets for characterization were produced in an industry-oriented way using a 100 kg induction furnace for ingot production, a laboratory-sized rolling mill for sheet production and circulating air furnaces for all heat treatments. In the following, all different compositions were characterized by tensile tests and bending tests. Metallographic analyses were used to examine the microstructures and evaluate the influence of dispersoid-forming elements like Cr or Mn.
Translated title of the contributionDevelopment of a high strength, good formable 6xxx automotive alloy
Original languageGerman
QualificationDipl.-Ing.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Schmid, Florian, Supervisor (external)
  • Pogatscher, Stefan, Supervisor (internal)
Award date20 Oct 2023
DOIs
Publication statusPublished - 2023

Bibliographical note

embargoed until 18-08-2028

Keywords

  • 6xxx
  • AlMgSi
  • wrought aluminium alloy
  • alloy development
  • solution treatment
  • paint-bake treatment
  • thermodynamic simulations
  • metallographic analyses
  • tensile test
  • bending test

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