Einfluss von Wärmebehandlung und Oberflächentopographie auf das Ermüdungsverhalten von additiv gefertigten Proben einer Al-Mg-Sc-Legierung

Translated title of the contribution: Influence of heat treatment and surface topography on the fatigue behaviour of additively manufactured samples of an Al-Mg-Sc alloy

Florian Bauer

Research output: ThesisMaster's Thesis


The aim of this thesis is to extend the knowledge about an Al-Mg-Sc alloy, known as Scalmalloy®, by characterizing the effect of thermal post-treatment and mechanical processing of the surface on fatigue strength. A developed methodology for the estimation of fatigue strength in the as-built surface condition, under consideration of local parameters such as characteristic roughness parameters and the existing residual stress state, makes a significant contribution to the fatigue strength evaluation of additively manufactured structures. Specimens produced by cooperation partners by means of selective laser melting were divided into three test series of 15 specimens each. Polished specimens without (Sc-BC) and with precipitation hardening (Sc-HT) as well as as-built specimens with precipitation hardening (Sc-HT(AB)) are examined. Thermal post-treatment is performed at a temperature 300°C over a period of 4h. The as-built surface topography is recorded three-dimensionally with a digital light microscope and characteristic roughness parameters are derived using a computer-aided evaluation routine. On average, a mean arithmetic height Sa of 11.83 µm is measured on the unmachined surfaces and the expected value of the largest maximum sink height Sv is evaluated to 43.81 µm. The mechanically processed sample series had a roughness of Ra 0.4 in the test area. The residual stresses present on the surfaces of the specimens are determined non-destructively using an X-ray diffractometer. Tensile residual stresses in the test section are measured in the amount of 40.9 MPa on the polished and heat-treated series, 67.4 MPa on the as-built and heat-treated series and 87.3 MPa on the polished and non-heat-treated series. The fatigue strength of the material is determined experimentally by vibration tests on round specimens at a (load) stress ratio R=-1 on a resonance testing machine. Fatigue strength is evaluated for the polished and heat-treated specimen series at 126.4 MPa, for the as-built and heat-treated series at 89.1 MPa and for the polished and non-heat-treated series at 51.6 MPa. Applying selected concepts, the fatigue strength is estimated by incorporating local material properties, residual stresses and surface parameters. Estimated fatigue strength is compared with experimentally determined data. The best agreement is achieved by a local concept with one percent deviation. The examined global concepts showed larger deviations of up to 21%.
Translated title of the contributionInfluence of heat treatment and surface topography on the fatigue behaviour of additively manufactured samples of an Al-Mg-Sc alloy
Original languageGerman
Awarding Institution
  • Montanuniversität
  • Leitner, Martin, Co-Supervisor (internal)
  • Schneller, Wolfgang, Co-Supervisor (internal)
  • Grün, Florian, Supervisor (internal)
Award date18 Dec 2020
Publication statusPublished - 2020

Bibliographical note

embargoed until 06-11-2025


  • Mechanical Engineering
  • Scalmalloy
  • Fatigue
  • Fatigue strength
  • Fatigue resistance
  • Additive Manufacturing
  • AM
  • Generative Manufacturing
  • 3D Printing
  • 3-D Printing
  • Selective Laser Melting
  • SLM
  • Al
  • Mg
  • Sc
  • Zr
  • Al-Mg
  • Al-Mg-Sc
  • Al-Mg-Sc-Zr
  • Aluminium
  • Scandium
  • Zirconium
  • Phase Diagram
  • Microstructure
  • Process window
  • heat treatment
  • precipitation hardening
  • dispersion hardening
  • residual stresses
  • residual stress measurement
  • X-ray diffraction
  • medium stresses
  • surface
  • roughness
  • surface parameters
  • surface analysis
  • fatigue test
  • medium stress correction
  • mean arithmetic height
  • maximum sink height
  • notch root radius
  • notch base radius
  • AlSi10Mg

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