Speaker
Description
The inherent inhomogeneity and cyclic thermal loading in metal additive manufacturing (AM) significantly change the evolution and hierarchy of microstructures compared to traditional (subtractive) processing methods. However, the same AM characteristics may enable targeted microstructure and property control once the current fundamental understanding of the underlying mechanisms has been extended.
In our own recent research as part of the AUSMURI project, we have made exciting discoveries which will enable engineering of microstructures for property control directly during 3D printing, without complex forming and thermal treatments in metallurgical plants.
This presentation will showcase handpicked recent insights obtained via use of multiscale correlative microscopy during AM of Ti-6Al-4V, Ni-based superalloys, and various stainless steels for defence, aerospace, and other high-performance applications.
Analysis of various interfaces formed during electron-powder-bed-fusion of Ti-6Al-4V clarifies the competition between different modes of alpha variant selection in determining the final microstructure. Understanding of the complexity of the alpha-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 important alloy.
Further current results are concerned with tuning the grain boundary character distribution, phase transformation behavior, texture evolution, and nanoprecipitation directly via variations of the AM scanning strategy in common Ni-based superalloys and stainless steels. Various light optical, scanning and transmission electron microscopy techniques combined with atom probe tomography are applied to obtain these insights.