Laser Powder Bed Fusion of a high strength Al alloy

Laser Powder Bed Fusion (LPBF) offers huge advantage in the manufacturing of complex geometries and intricate shapes. LPBF demands raw materials in a powdered form. Recently, a novel Al based composite powder namely A20X has been designed by Aeromet International Ltd., U.K. which offers light weight, high strength and reduced hot cracking susceptibility. A20X is an Al-Cu-Mg-Ag alloy reinforced with in-situ produced TiB2 particles. It is a heat treatable alloy which mainly derives its strength from the precipitation hardening. In the present study, we investigated LPBF processability, microstructural evolution under conventional T6 treatment and mechanical behaviour of A20X. At first the processability of the powder was assessed by analysing porosity values of samples built with different combinations of process parameters. Once the optimum building conditions were defined, the microstructural and mechanical characterisation of as-built and heat treated samples was carried out through optical and Scanning Electron Microscopies coupled with Energy-dispersive X-ray spectroscopy measurements. Phase identification was carried out through X-Ray Diffraction and their quantification was done by Rietveld refinement. Mechanical behaviour was characterised by the tensile stress-strain curves. In the end, the structure-property correlation of the material was established.