Ultrasonic Vibration-Assisted Cold Metal Transfer Direct Energy Deposition of Dissimilar SDSS2507–IN718 Alloy Parts: Microstructural and Mechanical Characterization

Cold metal transfer (CMT) has emerged as a highly promising method for directly producing or repairing high-performance metal components. Induced fabrication defects, like porosity and heterogeneous microstructures, impact part quality and mechanical performance. Investigating a high-efficiency CMT-based wire-arc direct energy deposition method is important for manufacturing high-quality, super duplex stainless steel 2507 (SDSS2507)–Inconel 718 (IN718) parts. Ultrasonic vibration has been used to enhance part performance in melting material solidification procedures. Few studies exist on using ultrasonic vibration in CMT-based wire-arc direct energy deposition for dissimilar SDSS2507–IN718 part production. This research proposes the use of ultrasonic vibration (UV)-assisted CMT-based wire-arc direct energy deposition to manufacture dissimilar SDSS2507–IN718 parts to potentially decrease fabrication faults. Experimental studies are carried out to examine the impact of ultrasonic vibration on the microstructures and mechanical properties of parts manufactured using CMT. The findings demonstrated that the application of ultrasonic vibration improved the microstructure, leading to an average grain size of 4.59 µm. Additionally, it effectively fragmented the harmful Laves precipitated phase into small particles that were evenly distributed. Consequently, the yield strength and ultimate tensile strength (UTS) of the fabricated dissimilar SDSS2507–IN718 parts were improved. The microhardness increases from an average of 302 HV to 335 HV, reflecting an 11% gain, at SDSS2507; from 233 HV to 265 HV at the Interface, indicating a 14% increase; and from 249 HV to 270 HV at IN718, demonstrating a 9% enhancement.