Influence of Ti Powder Additions on Microstructure and Mechanical Performance of PBF-LB AA6061

Abstract

Additive manufacturing of high strength 6xxx series aluminium alloys by powder bed fusion - laser beam (PBF-LB) is limited by hot cracking, driven by their wide solidification range and rapid cooling rates. Nanoparticle additions have shown success to mitigate cracking through grain refinement, but their adoption is restricted by high cost, processing challenges, and health and environmental concerns. This study investigates the use of micro-sized titanium powder as a sustainable alternative to suppress hot cracking during PBF-LB of AA6061 alloy. Commercial gas-atomized AA6061 powder (20–63 μm) was blended with Ti-6Al-4V powder (20–38 μm) at 1 wt% addition and processed with PBF-LB. Microstructural evolution and particle–matrix interactions were examined using LOM and SEM–EDS, while EBSD was used to analyse grain structure development. Aging response was assessed through hardness. The findings indicate that micro-sized Ti additions can influence microstructural refinement and mechanical behaviour, providing a practical strategy to improve the processability and mechanical reliability of additively manufactured 6xxx aluminium alloys.