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Lecture

WEB The microstructural effects on the mechanical properties of polycrystals: A comparative experimental-numerical study on conventionally and additively manufactured metallic materials

Wednesday (23.09.2020)
15:15 - 15:30 S: Structural Materials 1
Part of:


The understanding and hence exploitation of the connection between microstructure and mechanical properties of polycrystals is and continues to be at the forefront of the longstanding challenges in materials science and metallurgical engineering. Metal additive manufacturing (AM) provides an unprecedented opportunity to explore extreme microstructural regimes and their respective effects on the mechanical properties of polycrystals.

In this work, a single alloy (composition) was processed by a conventional thermo-mechanical treatment and two different AM processes. This resulted in three different materials with strikingly diverse microstructures with respect to the microstructural size and (textural and morphological) polarity. The influence of disparities in the statistical microstructural features arising from different processing conditions on (macroscopic) mechanical response was investigated through a hybrid experiment-simulation approach. The (as-processed/as-built) microstructures were analyzed on the meso-scale for derivation of a set of parameters, namely the meso-structure descriptors, which adequately describe the meso-structural heterogeneity features.

To link the microstructure and macroscopic mechanical properties, we used a physics-based crystal plasticity modeling approach in the framework of meso-scale full-field polycrystal homogenization. The meso-structure descriptors together with the submeso-scale/constitutive microstructural parameters were used to simulate the (anisotropic) mechanical response of the aforementioned materials. Then, for a reduced-order quantitative assessment of the microstructural polarity effect on the anisotropic mechanical response, the plastic anisotropy indices were defined and calculated using the simulation results. This study provides a profound understanding of the polycrystalline microstructural size and polarity effects on the stress and strain hardening responses as well as the propensity of the micro-mechanisms of polycrystal plasticity in highly different microstructural regimes, particularly those typically obtained by metal AM.

 

Speaker:
S. Amir H. Motaman
RWTH Aachen University
Additional Authors:
  • Fabian Kies
    RWTH Aachen University
  • Patrick Köhnen
    RWTH Aachen University
  • Dr. Christian Haase
    RWTH Aachen University