Priyanka Agrawal, Sanya Gupta, Saket Thapliyal, Shivakant Shukla, Ravi Sankar Haridas, Rajiv S. Mishra

An in-depth understanding of microstructure and resultant properties is paramount in the design of a novel alloy system, especially for additive manufacturing (AM). The present investigation aims to characterize a prototypical AM Al alloy with great potential for structural applications. An Al-1.5Cu-0.8Sc-0.4Zr alloy designed using integrated computational material engineering was printed using the laser powder bed fusion AM process. This novel alloy shows promising combination of strength and ductility in as-built and peak-aged conditions. This improvement in the tensile properties is attributed to the presence of both coherent L12 Al3Sc/Al3(Sc,Zr) precipitates and Cu-rich regions. The microstructures were studied via extensive microscopy at different length scales using X-ray microscopy, scanning electron microscopy, and transmission electron microscopy. Fractography revealed that the columnar grain boundaries in as-built condition allow easy slip transfer as compared to the equiaxed grains, with the apex of the melt pool acting as the crack nucleation site. However, the peak aged condition resulted in improved strength while marginally sacrificing ductility due to precipitates decorating dislocations, grain boundaries and melt pool boundaries thus acting as obstacles to slip transfer.

Keywords: Additive manufacturing; Aluminum alloys; X-ray microscopy; Texture; Fractography

Additive Manufacturing
Volume 37, 2021, 101623, ISSN 2214-8604,

https://doi.org/10.1016/j.addma.2020.101623

(https://www.sciencedirect.com/science/article/pii/S2214860420309957)