Investigation of Droplet + Arc Deposition Additive Manufacturing with WCP Simultaneous Reinforcement for Aluminum Alloy

A novel droplet + arc deposition additive manufacturing with ceramic particle simultaneous reinforcement has been proposed for the high-efficiency and low-cost fabrication of aluminum matrix composites. In the experimental study, the tilted variable polarity arc was used as heat source, Al2024 was used as the matrix and spherical WC particles were used as reinforcement phases. During the AM process, the droplets which generated from an independent generator fall vertically into the molten pool and the WC particles are feeding into the back edge of the molten pool simultaneously. The WC particles will disperse into the aluminum matrix with the relative motion of the arc and the substrate. The results show that the WC feeding direction, the flow rate of the carrier gas and the size of WC particle all have significant effects on the AM process. When the powder feeding direction is parallel to the axis of the tungsten needle, and the powder streams converge at the back edge of the molten pool, it is beneficial to maintain the stability of arc and obtain a high proportion of WC implantation. The metallographic analysis shows that the distribution of WC particles is generally uniform and the combination between WC particle and Al2024 matrix is reliable. The existence of WC will inhibit the growth of columnar crystals, and the grain size of matrix can be refined significantly when the WC size is less than 40 μm. © 2022 Journal of Mechanical Engineering.