Critical Quenching Rates After Solution Annealing: Peculiarities of Aluminum–Silicon Alloys Fabricated by Laser Powder-Bed Fusion

  • S. Hafenstein
  • L. HitzlerEmail author
  • E. Sert
  • A. Öchsner
  • M. Merkel
  • E. Werner
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)


Hot isostatic pressing is commonly used to reduce the porosity of (sand-)cast age-hardenable Al-alloys in order to meet the high quality requirements defined by aircraft and automotive industries. In order to establish additive manufacturing methods, such as laser powder-bed fusion (L-PBF), hot isostatic pressing can be utilized to reduce the anisotropic mechanical properties in as-built condition and at the same time eliminate porosity. For the cast aluminum alloy A356, a gas pressure of 75 MPa during hot isostatic pressing lowers the critical cooling rate required to achieve an oversaturated solid solution to about 1 K/s, which is significantly lower than the required quenchingrate at atmospheric pressure (2–4 K/s). Thus, an oversaturated state of dissolved magnesium and silicon atoms within the aluminum matrix of cast alloys can easily be achieved in modern hot isostatic presses, thereby avoiding the necessity of a separate solution annealing step. In this work, we applied hot isostatic pressing followed by rapid quenching and direct aging to age-hardenable aluminum alloys processed by both sand casting and laser powder-bed fusion. It was shown that the proposed process of direct aging could be utilized for post-heat treatment of additively manufactured age-hardenable aluminum alloys to open up new fields of applications, for which components have to possess a high fatigue resistance.


Laser powder-bed fusion Selective laser melting Additive manufacturing Fatigue resistance Hot isostatic pressing Critical cooling rate 


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Copyright information

© The Minerals, Metals & Materials Society 2020

Authors and Affiliations

  • S. Hafenstein
    • 1
  • L. Hitzler
    • 1
    Email author
  • E. Sert
    • 2
  • A. Öchsner
    • 2
  • M. Merkel
    • 3
  • E. Werner
    • 1
  1. 1.TUM Department of Mechanical Engineering, Institute of Materials Science and Mechanics of MaterialsTechnical University of MunichGarching bei MünchenGermany
  2. 2.Faculty of Mechanical EngineeringEsslingen University of Applied SciencesEsslingenGermany
  3. 3.Faculty of Mechanical Engineering and Materials ScienceAalen University of Applied SciencesAalenGermany

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