Metallic glasses made by selective laser melting (SLM): structuring, surface treatment and mechanical properties

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The aim of the project is the development of process chains for the use of iron- and zirconium-based metallic glasses in the production of delicate or compact component parts and the analysis of these process chains in relation to the effects of structuring processes and mechanical surface treatments on the mechanical properties of laser-melted specimens or cast specimens. Fe- and Zr-based metallic glasses, due to their great capability of producing high-strength materials, their great elastic deformability, and their good abrasion resistance in low dimensions, are well suited for use in micro-components under high loads, although insufficient cooling during the production process or too high temperatures during the structuring processes following production can lead to the formation of crystalline phases and thus to a loss of the desired properties. Hence, a new production route for metallic glasses will be developed: complex and delicate geometries will be realized by a layer by layer construction using selective laser melting (SLM) and including further development of given chemical compositions. Separation of supporting structures and treatment of functional surfaces results from subsequent structuring and modification treatments. In contrast, larger parts will be primary shaped by casting and subsequently structured.During these structuring surface treatments shear bands can be initiated in the metallic glasses: the shear bands have positive effects on the elongation to fracture and the fatigue properties. During the funding period the processes of laser melting with subsequent further treatment and casting with subsequent processing will be characterised and compared. Further treatment will include micro-milling, micro spark erosion and micro laser ablation. Further mechanical treatment in the form of shot peening and abrasive blasting is also envisaged and will be subsequently analysed. All process chains will be accompanied by characterisation and testing of the structural, mechanical and thermal properties of the samples. Thereby the focus is on the mechanical properties, namely the tensile and fatigue behaviour, as a function of the treatment parameters. By using different measuring methods the mechanical properties, the microstructure (shear band morphology), and the geometry of the surface structure will be correlated. Besides, possible changes of the microstructure during fatigue loading will be measured in situ with physical measurement methods. All results will be used to establish state-properties-correlations for the process chains.