The University of Queensland, School of Mechanical and Mining Engineering
Abstract
Wire Arc Additive Manufacturing is an innovative manufacturing process with great potential for production of large ribbed titanium aerospace components. Based on well-established and trusted welding technology, the process is extremely affordable, characterized by its potential for high deposition rates and free of the limitations associated with presently utilized additive manufacturing processes. However, given titanium’s extreme reactivity at high temperatures, an ongoing challenge is to prevent atmospheric contamination during out-of-chamber material deposition. This is especially important during additive layer manufacturing, as surface oxidation formed from previous layers is readily absorbed during deposition of subsequent layers. This engineering thesis explores the overall sensitivity of Ti-6Al-4V components to oxidation contamination during out-of-chamber Wire Arc Additive Layer Manufacturing (WAALM). Several sample conditions were produced through various argon trailing shield configurations and the changes in alloying element chemistry and mechanical properties evaluated. Other techniques, such as sand blasting to reduce re-inclusion of surface oxidation, were also investigated. This work aids in determining acceptable levels of surface oxidation during out-of-chamber wire arc additive manufacturing. Irrespective of the level of surface oxidation, no significant difference in chemical or mechanical properties were observed between each sample condition. Overall, more focus needs to be placed on providing quality wire feedstock and ensuring shielding at the melt pool, as opposed to qualitative analysis of surface oxidation
