Processability, microstructure and precipitation of a Zr-modified 2618 aluminium alloy fabricated by laser powder bed fusion

Additive manufacturing offers the opportunity to produce complex geometries from novel alloys with improved properties. Adapting conventional process-specific properties can facilitate rapid implementation of these materials in industrial practice. Nevertheless, processing by laser powder bed fusion is challenging, particularly cases pronounced susceptibility hot cracking. Previous studies have demonstrated positive influence zirconium on cracking high-strength aluminum alloys, although its precipitation formation, which immensely important for 2xxx remains largely unexplored. This work investigates optimum process parameters and formation 2618 modified fusion. The addition results production a crack-free, high-density (~99.9%) material. microstructure characterized trimodal grain size distribution. Very fine (~0.5 µm) equiaxed grains, nucleated L12-Al3Zr at melt pool boundary, followed columnar-dendritic grains (5–15 µm long, 1–3 wide) coarser (1–3 form during solidification. boundaries are populated predominantly (Al,Cu)9FeNi, but also Mg2Si, Al2CuMg, AlCu, presumably impede growth promote very fine-grained, low-textured microstructure, even regions where absent. as-built microhardness 1360 ± 74 MPa exceeds that known Al tailored additive manufacturing, Addalloy™ Scalmalloy®. provide better understanding precipitate Zr-modified series pave way commercialization further adapted manufacturing.