Effect of scanning strategy on microstructure and texture evolution in a selective laser melted Al-33Cu eutectic alloy

Abstract

Laser-based powder-bed fusion (LPBF) / Selective laser melting (SLM) was used to fabricate a eutectic composition of Al-33Cu alloys in-situ. Different scan strategies (1 × 1, 2 × 2, 3 × 3, 4 × 4, and 60°) were adopted to understand its effect on porosity, phase formation, microstructural and texture evolution, and mechanical properties. The 1 × 1 specimen showed the highest porosity among the hatch variation, and the 60° scan strategy showed the least. X-ray diffraction from the specimens prepared using different scan strategies showed a mixture of Al (face-centered cubic) and Al2Cu (body-centered tetragonal) phases. The microstructure of all the specimens revealed eutectic lamellar-type morphology; however, the interlamellar spacing was observed to be different at the melt and laser track-overlapped regions. The nano-lamellar eutectic microstructure exhibited a compressive strength exceeding 1 GPa. Nano-indentation in two distinct regions indicated an Al-rich softer zone and an Al2Cu rich harder zone. Bulk texture analysis was also done for both phases for all the hatch-varied specimens, and it shows a particular texture component intensifies from weak fiber as the scan strategy is altered.