Directed-energy deposition is a 3D printing method that uses a focused energy source, such as a plasma arc, laser, or electron beam to melt a material that is simultaneously deposited by a nozzle. As with other additive manufacturing processes, this technology is used to add material to existing components, for repairs, or to build new parts. Direct-energy deposition additive manufacturing techniques have gained much attention from the industry to build/repair in-service components. However, this process undergoes complex dynamics of melting and solidification raising challenges to the effective control of grain structure causing potential structural failure. This research study was conducted to investigate the potential of using high-intensity ultrasonic to control the solidification process and scaling up the system to manufacture large components. From the feasibility study, it was noted that ultrasonic can assist in the refinement of the grain structure and also reduce anomalies such as porosities. Under the feasibility study, a range of frequencies and power configurations were considered to ease the scale-up of the system. Based on the studied ultrasonic configurations, the 40 kHz 60 W configuration was finalized to use in the scale-up. It was also noted the reduction of hot cracks in the ultrasonic-assisted additive manufacturing due to the constitutional supercooling during solidification by lowering the temperature gradient in the bulk of the melt pool. Furthermore, it was also noted that the grain orientation is perpendicular to the direction of vibration which potentially can be used to control the orientation of the grains as required. This new finding provides new applications to exploit the ultrasonic-assisted additive manufacturing process.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)