Mechanism-based investigation of additively-manufactured aluminium matrix composites (AMC) for enhanced mechanical strength

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The processing of aluminium matrix composite (AMC) powders by means of additive manufacturing will offer the possibility to manufacture tailor-made AMC components. It requires a detailed investigation of involved chemical reactions, composition and phase transformations during high energy ball milling (HEBM) and the selective laser melting (SLM) processing. The main focus is on SiC particles reinforced AlSi10Mg powder. The following scientific questions are to be investigated: How does the shape of the composite powder particles effect the processibility by means of SLM? What is the role of process control agent residues during SLM? How do the typical properties of HEBM microstructures influence the processing by SLM? Which defects occur in SLM for the HEBM-processed AMC powders? How do the microstructures of SLM-processed materials influence the mechanical properties? Fatigue behaviour plays an important role in structural applications. The specific microstructure and remnant porosity induced by the SLM process reflects complicated fatigue damage phenomena. Secondary phase reinforcements are foreseen to result in different cyclic loading interactions with microstructural constituents. Interfaces at reinforcements and phase boundaries are expected to induce multiple damage and failure initiation. This challenge dictates that understanding of multi-scale strength attributes of macro- and micro-level structures is necessary. The findings obtained from mechanical tests and microstructural investigations will be used to understand mutual interaction between manufacturing and properties at various scales and investigate: What are the most sensitive process parameters? How do the processing routes effect the mechanical properties (fatigue behaviour, tolerances against manufacturing deviations)? The basic understanding of deformation mechanisms in the SLM-AMC process chain will open the door for further effective exploitation in industrial and structural applications and will highlight future fundamental research aspects.