Titanium base alloys for laser powder bed fusion

Christian Fleißner-Rieger

Research output: ThesisDoctoral Thesis

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Abstract

Ti base alloys are commercially used for various applications in almost all industrial sectors. The material-specific benefits, such as high strength, low density and high corrosion resistance, excellently suits the aerospace, automotive and medical industry requirements, which is why these industries are the prominent driving forces for the research and development activities in the Ti industry. The combination with the additive manufacturing technology enables to link the beneficial material specifics of Ti base alloys with the eco-design concept supporting low material waste and freeform fabrication ability. Although additively manufactured Ti base alloys are already used, the alloy portfolio is limited and almost reduced to the Ti 6Al 4V alloy. Hence, this thesis deals with the implementation of other Ti base alloys, such as the Ti-6Al-2Sn-4Zr-2Mo-Si alloy for laser powder bed fusion, and explores process limits and achievable mechanical properties. Via in-depth characterization techniques such as high-energy X-ray diffraction, transmission electron microscopy, differential scanning calorimetry and atom probe tomography, this thesis aims to enhance the fundamental understanding of the material response on the laser powder bed fusion process. Furthermore, it points out that analogies to well-investigated materials such as the Ti-6Al-4V alloy help to accelerate the implementation process based on a higher troubleshooting efficiency and already existing manufacturing know-how. In addition, martensitic phase transformations are investigated, displaying the potential use of a ‘softer’ martensite. Soft martensite was found to form in bulk materials when the solidification process is accelerated. Finally, the precipitation behavior of near α and α+β alloys was investigated in detail. The generated understanding of the decomposition of supersaturated phases enables the implementation of optimized post-process heat treatments.
Translated title of the contributionTitan-Basislegierungen für das selektive Laserschmelzen
Original languageEnglish
QualificationDr.mont.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Kiener, Daniel, Assessor B (internal)
  • Stockinger, Martin, Assessor A (internal)
  • Clemens, Helmut, Supervisor (internal)
  • Eckert, Jürgen, Co-Supervisor (internal)
Publication statusPublished - 2022

Bibliographical note

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Keywords

  • Materials Science
  • Additive manufacturing
  • Titanium alloys
  • Material Characterization
  • Alloy development

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