Control of Crystallographic Texture in Powder Bed Fusion Additive Manufacturing of Intermetallics and the Related Superalloys

Additive manufacturing (AM) enables the production of complex, net-shape geometries. Additionally, in AM of intermetallic compounds and the related superalloys, which has received less attention, the microstructure and crystallographic texture of the product can be arbitrarily controlled by selecting appropriate process parameters, thereby enabling unprecedented superior properties. This paper discusses recent progress pertaining to texture evolution mechanisms and control methods, with an emphasis on laser-beam and/or electron beam powder bed fusion (PBF). One of the unique characteristics of PBF is that the crystallographic texture can be varied as a function of position within the product by controlling the scan strategy. The transient behavior of the texture and the factor used to control it via the scan strategy are discussed. In addition, the texture evolution behavior of highly symmetrical Ni-base superalloys as well as relatively low symmetrical TiAl intermetallic compound and disilicide is discussed. The importance of the crystallographic, multiplicity, of the preferential crystal growth direction is described to understand the evolution behavior of the texture in such heat-resistance materials.<br/><br/>This study was supported by Grants-in-Aid for Scientific Research (JP18H05254) from the Japan Society for the Promotion of Science (JSPS). This study was also partly supported by Council for Science, Technology and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP), Materials integration, for revolutionary design system of structural materials, from the Japan Science and Technology Agency (JST).