Influence of deposition strategy on the microstructure of volumetric WADED-fabricated AZ61 magnesium alloy components

Abstract

This study investigates the impact of various deposition strategies on the microstructure of volumetric components fabricated from AZ61 magnesium alloy using Wire Arc Direct Energy Deposition (WADED), also referred to as Wire Arc Additive Manufacturing (WAAM). Because coarse grains can significantly reduce mechanical performance, thermal simulations were performed to identify low-cooling-rate regions associated with different deposition trajectories. Three deposition strategies were analysed: ZigZag, Spiral, and S-pattern. The simulated thermal profiles were validated by optical grain size analysis and hardness measurements. In the selected critical regions, where the largest grains are expected, the S-pattern achieved the narrowest range in grain size and hardness distribution. This trajectory also exhibited the finest microstructure in the most critical region, with the smallest average grain size. Additionally, it maintained good geometrical accuracy, indicating that it offers a promising route for producing high-quality magnesium-alloy components via WADED.