Comparison of the Hot Working Behavior of Wrought, Selective Laser Melted and Electron Beam Melted Ti-6Al-4V

Abstract

The production of high-temperature components is of great importance for the transport and energy sector. Forging of high-temperature alloys often requires expensive dies, multiple forming steps and leads to forged parts with large tolerances that require machining to create the final shape. Additive manufacturing (AM) offers the possibility to print the desired shapes directly as net-shape components. AM could provide the advantage of being more energy-efficient compared to forging if the energy contained in the machining scrap exceeds the energy needed for powder production and laser processing. However, the microstructure and performance of 3D-printed parts will not reach the level of forged material unless further processes such as hot-isostatic pressing are applied. Combining AM and metal forming could pave the way for new process chains with little material waste, reduced tooling costs and increased part performance. This study investigates the hot working properties and microstructure evolution of Ti–6Al–4V pre-forms made by selective laser melting and electron beam melting. The results show that both materials are hot workable in the as-built state. Due to its martensitic microstructure, the SLM material shows a lower activation energy for hot working than EBM and wrought material and a faster globularization during forming, which is beneficial for hot forming since it reduces the forming forces and tool loads.