Filters

2020 - 20212

More filters

2020 - 20212
Reset filters

Settings

End date: 2024 × Start date: 2020 × DDC: 620 × Version: publishedVersion × Subject: additive manufacturing × WGL Institute: IFWD ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Viscous Flow of Supercooled Liquid in a Zr-Based Bulk Metallic Glass Synthesized by Additive Manufacturing
    (Basel : MDPI, 2020) Kosiba, Konrad; Deng, Liang; Scudino, Sergio
    The constraint in sample size imposed by the critical cooling rate necessary for glass formation using conventional casting techniques is possibly the most critical limitation for the extensive use of bulk metallic glasses (BMGs) in structural applications. This drawback has been recently overcome by processing glass-forming systems via additive manufacturing, finally enabling the synthesis of BMGs with no size limitation. Although processing by additive manufacturing allows fabricating BMG objects with virtually no shape limitation, thermoplastic forming of additively manufactured BMGs may be necessary for materials optimization. Thermoplastic forming of BMGs is carried out above the glass transition temperature, where these materials behave as highly viscous liquids; the analysis of the viscosity is thus of primary importance. In this work, the temperature dependence of viscosity of the Zr52.5Cu17.9Ni14.6Al10Ti5 metallic glass fabricated by casting and laser powder bed fusion (LPBF) is investigated. We observed minor differences in the viscous flow of the specimens fabricated by the different techniques that can be ascribed to the higher porosity of the LPBF metallic glass. Nevertheless, the present results reveal a similar overall variation of viscosity in the cast and LPBF materials, which offers the opportunity to shape additively manufactured BMGs using already developed thermoplastic forming techniques.
  • Thumbnail Image
    Item
    Laser Powder Bed Fusion Processing of Fe-Mn-Al-Ni Shape Memory Alloy - On the Effect of Elevated Platform Temperatures
    (Basel : MDPI, 2021) Ewald, Felix Clemens; Brenne, Florian; Gustmann, Tobias; Vollmer, Malte; Krooß, Philipp; Niendorf, Thomas
    In order to overcome constraints related to crack formation during additive processing (laser powder bed fusion, L-BPF) of Fe-Mn-Al-Ni, the potential of high-temperature L-PBF processing was investigated in the present study. The effect of the process parameters on crack formation, grain structure, and phase distribution in the as-built condition, as well as in the course of cyclic heat treatment was examined by microstructural analysis. Optimized processing parameters were applied to fabricate cylindrical samples featuring a crack-free and columnar grained microstructure. In the course of cyclic heat treatment, abnormal grain growth (AGG) sets in, eventually promoting the evolution of a bamboo like microstructure. Testing under tensile load revealed a well-defined stress plateau and reversible strains of up to 4%.