Efficient depositing aluminum alloy using thick strips through severe deformation-based friction rolling additive manufacturing: processing, microstructure, and mechanical properties

Abstract

Solid-state additive manufacturing is a promising technology for production of high-strength aluminum alloy components. However, most solid-state AM technologies use thin foils or powder as feeding materials, limiting the deposition thickness of each layer and thus restricting deposition efficiency. This study is the first to utilize 2-mm-thick 5052-H32 aluminum alloy strips as feed material for a severe deformation-based friction rolling additive manufacturing (FRAM) method. In this study, the effect of process parameters such as rising height, transverse speed, and rotational speed, on the forming quality, microstructure, and mechanical properties of the resulting part were investigated. The results indicated that macroscopic forming defects can be avoided by selecting appropriate process parameters. A non-planar lamellar microstructure of fine and ultra-fine equiaxed grains densely embedded in each other was obtained without porosity or unbound defects; although the deposited material was not composed of completely equiaxed grains, the anisotropy of mechanical properties was small. The ultimate tensile strength and elongation in both the longitudinal and build directions of deposited material were higher than those of the raw feeding strips owing to the non-planar lamellar microstructure and grain refinement, with maximum values of 215 MPa and 32%, respectively. Through this microstructure analysis, the mechanism behind the formation of the lamellar microstructure was elucidated. The concepts investigated here regarding defect-free, high strength, and high elongation lamellar materials by FRAM with thick strips as feeding material, provides a methodology for future preparation of laminated composites using FRAM.