Metal Additive Manufacturing Conference - MAMC 2021

The inherent inhomogeneity and cyclic thermal loading in metal additive manufacturing (AM) significantly change the microstructural evolution and various types of solid/solid interfaces compared to traditional routes. However, the same AM characteristics will enable targeted microstructure and property control if the current fundamental understanding of the underlying phenomena can be extended.

In our own recent research as part of the so-called AUSMURI project, we have made exciting discoveries which enable tuning of interface characteristics for property control directly during 3D printing, without complex thermo-mechanical treatments in large metallurgical plants. This presentation will showcase selected recent results on the role of interfaces during AM of Ti-6Al-4V and various stainless steels for defence and other applications.

Analysis of various interfaces formed during electron-powder-bed-fusion of Ti-6Al-4V clarifies the competition between different modes of -variant selection in determining the final microstructure. Understanding of the complexity of the -laths in 3D using plasma focused-ion-beam serial sectioning and electron back-scatter diffraction provides new insights into the fundamental phenomena behind the microstructural evolution in this alloy [1-4].

Further current results are concerned with tuning the crystallographic and chemical grain boundary microstructure and related mechanical and corrosion properties in austenitic, duplex and precipitation hardening stainless steels. This is achieved either directly via variations of the laser-powder-bed-fusion scanning strategy and/or short post-processing heat treatments [5,6].

References

[1] P.L. Stephenson, N. Haghdadi, R. DeMott, X. Liao, S.P. Ringer, S. Primig, Additive Manufacturing 36 (2020) 101581.
[2] N. Haghdadi, R. DeMott, P.L. Stephenson, X. Liao, S.P. Ringer, S. Primig, Materials & Design 196 (2020) 109177. OPEN ACCESS
[3] R. DeMott, N. Haghdadi, X.Z. Liao, S.P. Ringer, S. Primig, Journal of Materials Science 56 (2021) 14763-14782.
[4] R. DeMott, N. Haghdadi, Z. Gandomkar, X.Z. Liao, S.P. Ringer, S. Primig, Materialia 20 (2021) 101201. OPEN ACCESS
[5] N. Haghdadi, M. Laleh, M. Moyle, S. Primig, Journal of Materials Science 56 (2021) 64-107. OPEN ACCESS
[6] M. Laleh, A.E. Hughes, M.Y. Tan, G.S. Rohrer, S. Primig, N. Haghdadi, Scripta Materialia 192 (2021) 115-119.