Effects of wire diameter on mechanical and microstructural properties of Inconel 625 fabricated by wire arc additive manufacturing

This study aims to characterize Inconel 625 (IN625) alloy produced by the Wire Arc Additive Manufacturing (WAAM) process, focusing on the impact of wire diameter variation on key mechanical properties like tensile and impact toughness and hardness. Fracture surface morphology was analyzed from tensile and Charpy tests to gain insights into types of failure under different loads across the samples. The results indicated a strong correlation between the wire diameter and the material's strength and ductility. Tensile strength increases as wire diameter decreases, while ductility decreases slightly with decreasing wire diameter. Hardness also follows a similar trend as tensile strength, showing higher values for the smaller wire diameter and the least for the largest diameter. However, ductility was found to decrease with decreasing wire diameter, as expected. These trends can be attributed to grain size, which decreases with decreasing wire diameter. Finer grains promote mechanical strength but negatively affect ductility. Also, the findings indicated that variations in mechanical properties typically microhardness revealed the anisotropic nature, and the results varied with wire diameter. Generally, tensile strength and microhardness tests show that increasing wire diameter decreases their values, while impact strength shows the opposite trend and vice versa. From fracture analysis, micro-void formation, and coalescence result in a crack morphology consisting of tearing and prolific, in some areas there are cup-like depressions known as ductile dimples. The results contribute to optimizing the WAAM products with wire diameters for producing high-performance IN625 components with variations of wire diameter.