Minimizing the buy-to-fly ratio of aircraft structural parts made from milled Ti-6Al-4V is an important step in reducing the environmental impact of the aerospace industry. One possible way to achieve this goal is through wire and arc additive manufacturing (WAAM), an additive manufacturing technique based on arc welding. It is a cost-effective process with a minimal lead-time and significantly reduces material waste through near-net-shape manufacturing.
There are numerous process-related influencing factors on the feasibility, microstructure and mechanical properties. In previous investigations, we determined the most relevant WAAM-process parameters and developed an in-depth understanding on the process-parameter-microstructure-properties correlation [1, 2]. One of these parameters is the interlayer temperature [3] in between the individual layer depositions, as this parameter governs the cooling rate of the already consolidated subjacent layers. Thus, during layer deposition, an intrinsic heat treatment occurs that influences the microstructure and mechanical properties.
In this work, samples with different interlayer temperatures and two different cooling rates achieved by the using air curtains are investigated. The aim is to establish a correlation between process parameters, microstructure and mechanical properties. The samples were analyzed in terms of their microstructure and mechanical properties using Scanning Electron Microscopy, tensile and compression tests as well as advanced methods such as high-energy x-ray diffraction.
Effects of the interlayer temperature and varying cooling rates and thus the influence of the intrinsic heat treatment on the microstructure and mechanical properties were evaluated. These results highlight the importance of comprehensively understanding the impact of thermal management on the production of Ti‑6Al‑4V components.
References
[1]    D. Elitzer, H.W. Höppel, M. Göken, D. Baier, C. Fuchs, H. Bähr, T. Meyer, A. Gallasch, MATEC Web Conf. 2020, 321, 03037.
[2]    D. Elitzer, S. Jäger, C. Höll, D. Baier, R. Varga, M.F. Zaeh, M. Göken, H.W. Höppel, Adv. Eng. Mater. 2022, 24, 2201025.
[3]    C. Fuchs, D. Elitzer, H.W. Höppel, M. Göken, M.F. Zaeh, Prod. Eng. 2023.