Optimierung der mechanischen und gießtechnologischen Eigenschaften der Sekundärgusslegierung A226

Translated title of the contribution: Optimization of the mechanical and casting properties of the secondary foundry alloy A226

Philip Pucher

Research output: ThesisDoctoral Thesis

Abstract

The production of cast aluminum alloys is increasingly processed by the secondary route, rather than by primary metallurgy which is more expensive. High energy demand for the production of primary aluminum, the need to recycle residues, efforts in energy reduction and minimizing the emissions leads to a significant increase in secondary aluminum production in the recent years. The most commercially used secondary foundry alloy A226 (permanent mold casting variant AlSi8Cu3, high pressure die casting variant AlSi9Cu3) has a very wide tolerance range of the allowed alloying elements. This primarily provides the possibility to produce the alloy with many different types of scrap. On the other hand the complex effect of the alloying elements can cause significant fluctuations of the castability and mechanical properties. This affects the process stability and leads eventually to inadequate component quality. The main aim of this work was to evaluate and improve the mechanical and casting properties of the secondary foundry alloy A226 within the tolerance limit. For this reason the introduction gives a short overview about the effect of potential alloying elements in Al-Si casting alloys, the consideration of the possible resulting intermetallic phases and the significant influencing factors which are acting on the mechanical properties. The base for experimental investigations of mechanical and casting properties are industry-related permanent mold casting experiments. The yield strength varies between 110 and 400 MPa, while the values for elongation are between 0.35 to 7%. The fluidity could be doubled within the alloy tolerance limit. In addition to the evaluation of the specification profile of the A226, the development of ductile secondary foundry alloys within the tolerances of the A226 for the adaption of real castings was furthermore a central point. Under selected conditions the elongation to fracture in T6 temper was achieved by almost 20%. The final experimental part is engaged with the corrosion behavior of the A226 to find other possible applications in the automotive industry. Thereby the assumption that Cu has the most significant influence could be confirmed and it was found that levels between 0.3 – 0.6% a major intensity change in corrosion attack. On basis of the performed experiments in this work, it was possible to generate the software algorithm AMAG TopCast® Alloy Designer. According to the chemical composition and the local microstructure this software tool gives a forecast of the expected performance of the mechanical and casting properties.
Translated title of the contributionOptimization of the mechanical and casting properties of the secondary foundry alloy A226
Original languageGerman
QualificationDr.mont.
Supervisors/Advisors
  • Antrekowitsch, Helmut, Assessor A (internal)
  • Uggowitzer, Peter, Assessor B (external)
Publication statusPublished - 2011

Bibliographical note

embargoed until 15-03-2016

Keywords

  • A226
  • AlSi9Cu3(Fe)
  • aluminium foundry alloy
  • mechanical properties
  • casting properties

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