Project 8: Evaluation of additive manufacturing for RM-Si(-B-X) based substrates
The conventional production and machining of components made of refractory metal silicide alloys is made difficult by their high brittle-to-ductile transition temperature. The use of modern additive manufacturing processes promises component production close to the final contour with only minimal finishing work. With respect to additive manufacturing of high temperature structural metallic materials and intermetallic compounds, electron beam melting (EBM) is promising production technique. With base plate temperatures of up to 1100 °C, thermal cycling around the BDTT can be avoided during the process. Since the process also takes place under vacuum, the oxidation of the powder particles during the manufacturing process can be reduced. In this subproject of the graduate school, process conditions are to be found with which crack-free workpieces of eutectic Mo-Si-Ti alloys can be manufactured using the EBM process. The influence of the high cooling rates during additive manufacturing and the thermal gradients on the microstructure and mechanical properties of the alloys will be investigated. In addition, the influence of subsequent heat treatments on the microstructure of additively manufactured workpieces is investigated. Furthermore, it shall be clarified whether the results of the investigations on the local chemical composition, the lateral expansion of the phases and the texture as a function of the process parameters can be linked to the mechanical properties and the oxidation resistance.