Electro-plasticity in Al-Cu eutectic alloys

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The ultimate aim of this proposal within the SPP 'Manipulation of Matter Controlled by Electric and Magnetic Fields: Towards Novel Synthesis and Processing Routes of Inorganic Materials' is to unravel some of the underlying mechanisms facilitating enhanced plasticity during electro-mechanical deformation in otherwise brittle materials. To this end, an integrated computational materials engineering (ICME) approach is pursued by coupling a range of characterization techniques with mechanism-based multi-scale simulations in Al-Cu eutectic alloys. A better understanding of the electro-plastic effect in these alloys enables novel processing routes for more general metallic-intermetallic composite materials and thereby widening the technological application of this versatile class of materials. Complementary experimental and theoretical investigations of the electro-mechanical deformation behaviour of Al-Cu eutectic alloys are proposed with the aim to enhance the strength and formability of cast Al-Cu eutectic alloys. Specifically, we will synthesize Al-Cu alloys with varying microstructures using rapid alloy prototyping and characterize their electro-mechanical behaviour. Further, in-situ microscale electro-plasticity experiments using nano-indentation and micropillar compression will be performed to shed light on the influence of the electro-plastic effect in the different microstructural constituents. Meso- and microscale microstructure characterization using scanning electron microscopy, conventional and high resolution transmission electron microscopy, and atom probe tomography will be performed to investigate the local microstructural influence of the electro-plastic effect and correlate it with the macroscopic mechanical properties. All experimental data will be used as input and validation parameters for multi-scale simulations of the electro-plastic effect. Here the constitutive theory developed by Conrad et al. for the electron wind contribution to the plastic strain-rate will initially be used to adapt existing crystal plasticity constitutive laws. Additional factors such as joule heating and its effect on thermal expansion and softening will also be considered. The computational implementation will be performed within the flexible simulation toolkit DAMASK, and will be applied to study the electro-mechanical deformation mechanisms in relation to the underlying microstructure of the Al-Cu alloys.