Influence on microstructure and surface properties of FeCrMo filler-Nickel based alloy by wire arc additive manufacturing with severe shot peening and physical vapour deposition coating

The wall used in this study was made with 2205 (FeCrMo) filler wire and nickel-based (NAB) alloy plate utilising the WAAM procedure. As WAAM samples, the two distinct surface hardening procedures were performed: (i) WAAM-severe shot peening (SSP) and (ii) WAAM-SSP coating, which enhances the surface characteristics. Widmanstatten crystals (WC), α'ferrite structure, and solid crystal austenite structure (SCA) were observed in the WAAM-SSP sample. The (α+β) martensite, FeCr, NiCrMo, austenite, and secondary ferrite structures were formed as a result of heat inputs on WAAM-SSP coated samples reflecting on the outer surface. Grain length and fracture of grain boundaries growth of WAAM-SSP coated samples have reached 0.729 and 4.40 mm. In comparison to WAAM-SSP samples, the outer surface layers of WAAM-SSP coated samples had 8% higher hardness values. The hardness value of WAAM-SSP coated on Fe-lattice structure, CrMo phase, CrFe2O4 phase, and MnSi phase was observed to reach 312±5 HV, the hardness value of WAAM-SSP was achieved at 289±5 HV. All WAAM samples underwent wear tests, revealing fewer cavities and grooves. The AFM investigation revealed the various ranges: −800 to −500 nm for WAAM samples, 1.2–1.8 µm for WAAM-SSP samples, and 0.8–2 µm for WAAM-SSP coated samples.