Microstructural and intergranular corrosion properties of Inconel 625 superalloys fabricated using wire arc additive manufacturing

Abstract

Inconel 625 superalloy samples were fabricated using wire arc additive manufacturing (WAAM). The phase composition, microstructure, anti-corrosion, and mechanical properties of the Inconel 625 WAAM samples were analyzed. The microstructure of the Inconel 625 WAAM alloy showed good forming quality, no defects, and good metallurgical bonding within the specimens. The metallographic structure exhibited primarily γ-Ni and granular precipitated phases; the average microhardness of the transverse and longitudinal cross-sections of the sample was 243.5 and 243.3 HV0.1, respectively. Yield and tensile strength as well as elongation, decrease in area, and the room-temperature impact values of this alloy were equal to 450 and 736 MPa, 38% and 52%, and 152 J, respectively. The intergranular corrosion test results indicated that the average corrosion rate of the sample is 0.609 mm/year, indicating excellent resistance to intergranular corrosion.

Mitigating the susceptibility to intergranular corrosion of alloy 625 by friction-stir welding

“…In addition, some authors mentioned that the threshold for sensitization in the industry is 1 mm/year 13 , thus an acceptable friction-stir-welded alloy 625 was obtained. It is worth noting that authors 32 showed that Inconel 625, produced by wire-arc additive manufacturing (WAAM), reached an average corrosion rate of 0.609 mm/year (slightly higher than that of the current work), which was then suggested to have an excellent resistance to intergranular corrosion. Furthermore, for Inconel 686, a nickel-based alloy that was processed by fusion welding processes such as gas metal-arc welding (GMAW) and gas tungsten-arc welding (GTAW), the corrosion rate was respectively 2.5 mm/year and 2.3 mm/year 33 .…”

Friction Stir Welding: Mitigating the Susceptibility to Intergranular Corrosion of Alloy 625

“…In addition, some authors mentioned that the threshold for sensitization in the industry is 1 mm/y [13], thus an acceptable friction-stir-welded alloy 625 was obtained. It is worth noting that authors [26] showed that Inconel 625, produced by wire-arc additive manufacturing (WAAM), reached an average corrosion rate of 0.609 mm/year (slightly higher than that of the current work), which was suggested to have an excellent resistance to intergranular corrosion. Furthermore, for Inconel 686, another nickel-based alloy that was reported to be processed by gas metal-arc welding (GMAW) and by gas tungsten-arc welding (GTAW), the corrosion rate was respectively 2.5 mm/y and 2.3 mm/y [27].…”

A review on microstructure and mechanical properties of Inconel 625 alloy fabricated using wire arc additive manufacturing process

“…AM is classified into several categories based on the process being used for deposition, as shown in Figure 1; it includes powder bed fusion (PBF), direct energy deposition (DED), photopolymerization, material jetting, binder jetting, material extrusion and sheet lamination. Metal AM is mainly categorized into two groups, namely, DED and PBF (Guo et al , 2021).…”