Examples of micro-mechanical experiments performed on Scalmalloy
Correlative micro-mechanical experiments to characterize the effect of heterogeneities in
additively manufactured aluminium alloys
Researcher: Dr. Soudip Basu, Technische Universität Berlin, Chair of Materials for Additive Manufacturing
Measuring facility: ZELMI: Center for Electron Microscopy (TU Berlin)
Additive manufacturing of metallic systems generates large numbers of heterogeneities at multiple length scales. To effectively leverage the benefits of additive manufacturing, we need to understand and exploit these heterogeneities to obtain desirable mechanical properties. In the current project, pure aluminium and two different aluminium alloy compositions (pure Al, Al-Mg and Al-Mg-Ti-Zr) with increasing degree of chemical and microstructural complexity will be investigated to understand the (micro)structure-property correlations. This will help to design beneficial microstructures by utilizing the underlying the process-structure correlations as part of a larger effort to understand the complete design space in additively manufactured aluminium alloys as a model material. To the above end, correlative micromechanical experiments like microscopic digital image correlation (μDIC), geometrically necessary dislocation (GND) density mapping by electron backscattered diffraction (EBSD), hardness mapping, and macroscopic mechanical property measurements will be performed inside a scanning electron microscope. The obtained results will be analysed and used to explain the deformation behaviour at the microstructural length scale. The following figure illustrates an example of the results obtained for another aluminium alloy (Al-Mg-Sc-Zr) alloy, Scalmalloy. As can be seen in the figure below, data from such micromechanical experiments can be used to discern deformation mechanisms in these complex microstructures. In the example given here, strain accumulation seems to be more prevalent in the coarse-grained melt interior regions, while GND density localizes at the interface between fine- and coarse- grained regions due to the load sharing between these regions of different strengths.
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