Solid state recycling of aluminium with pulsed electric current sintering

Bernhard Kronthaler

Research output: ThesisMaster's Thesis


As a consequence of current trends many industrial branches show a growing demand for aluminium. In this context, recycling has become a popular strategy since it offers the benefits of preserving natural resources, reducing environmental impact as well as cutting costs. Due to their higher efficiency compared to conventional remelting, solid state recycling processes are a promising option. This master thesis concentrates on the use of pulsed electric current sintering (PECS) for direct conversion of aluminium chips. Although the interest in PECS has been growing rapidly throughout the last decades, in particular its use for metal chip recycling has not been considered frequently. The main goal of this work focussed on a deeper understanding of the influencing factors in PECS and their importance for processing of aluminium chips. The study includes theoretical research as well as experiments at the Chair of Metal Forming. At first an introduction into aluminium recycling is given and differences between remelting and solid state recycling are elaborated. The sections on theoretical background of PECS comprise characteristics and applications of the process as well as mechanical, thermal and electrical phenomena involved in sintering. Subsequently typical process parameters and tool features, reported for the processing of different aluminium input materials, are described. Furthermore, measurement options during sintering and methods to evaluate sample properties are covered. As empirical work pre-pressed chip samples of different densities were sintered using a thermo-mechanical simulation system. The steps of material preparation, tool design and processing including calibration are addressed. Additionally experiments performed on a designated PECS system at TU Bergakademie Freiberg are described. Subsequently the results of both test series are presented and discussed. It can be concluded that both higher temperature and pressure show a positive influence on sintering results. The sample density could be increased through sintering and the chips show better bonding. Nevertheless the levels of temperature, current and pressure used in the experiments do not lead to a fully dense homogeneous material, but the critical role of plastic deformation at elevated temperature could be validated. For future PECS experiments recommendations concerning tooling and parameters are given. This means in particular a higher current density and plastic deformation.
Translated title of the contributionSolid State Recycling von Aluminium durch Pulsed Electric Current Sintering
Original languageEnglish
Awarding Institution
  • Montanuniversität
  • Stockinger, Martin, Supervisor (internal)
  • Cislo, Clemens, Co-Supervisor (internal)
Award date20 Dec 2019
Publication statusPublished - 2019

Bibliographical note

embargoed until null


  • Recycling
  • Aluminium
  • Sintering

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