Process Study On Aluminum Alloy By Friction Stir Additive Manufacturing

At present, the common used method of additive manufacturing for metal is Direct Metal Laser-Deposition, Selective Laser Melting, Electron Beam Fused-Deposition, Electron Beam Selective Melting, Plasma Arc Fused-Deposition and Ultrasonic Additive Manufacturing. These methods have their respective applicable scope and limitations. There is no big progress in additive manufacturing for light alloy, such as aluminum alloy. It is necessary to develop a new method to achieve the goal of additive manufacturing for Aluminum alloy. This study uses homemade forming tools and special fixtures. Based on the theory of friction stir welding,a green and environmentally friendly solid-phase welding method is presented for 5A03-Aluminum alloy additive manufacturing. the zero tilt angle forming tools and fixtures are developed in this study. The influence of the process parameters on the formation of FSAM zone was investigated and the method of FSAM was explored.The influence of the process parameters on the formation of FSAM zone was studied in this paper systematically. The results show that, the FSAM zone forms good by the double-wire type forming tool. With the traveling speed increased, the width of the AFS zone, the height and width of interface migration are decreased respectively. The amount of interface migration is small and the width of interface migration in single pass is more than in the multiple pass when the traveling speed is 60mm/min. There are uncombined interface and migration interface between two adjacent passes when the FSAM space is big. Uncombined interface transforms into migration interface with the space decreasing. Migration interface disappears when the FSAM space reaches the appropriate value. The FSAM space should be optimized so as to get excellent FSAM zone. Compared with the same direction FSAM, the bigger width of FSAM zone can be obtained when the processing is in reverse direction because the migration of interface can be restrained and eliminated effectively. The influence of turning radius to FSAM forming in same direction is different in reverse direction. When in same direction, γ/D fluctuates and H/W is stable with the turning radius changes. When in reverse direction, H/β fluctuates and W is stable with the turning radius changes.This paper is concentrated on exploration of FSAM on Aluminum alloy. The results show that, the plan and calculation method of FSAM is accurate to forecast the Dr/Hr/ ξ. The results show in microstructure analysis, the grains are directional in the Shoulder-Affected Zone, the equiaxed grains are homogeneous, small and non-directional in the Additive Manufacturing Nugget Zone. The results show in performance test, the FSAM pieces have anisotropies in tensile strength. In horizontal direction, tensile strength of the pieces is 5% more than base material. In vertical direction, Its tensile strength is 85% of the base material. The hardness curve is distributed as ―W‖ shape in every FSAM layer. The hardness gradient exists in the vertical direction, the hardness in upper layer is higher than lower layer, The hardness of FSAM zone is not less than base material.