Improving Comprehensive Properties of Wire ArcAdditively Manufactured Al-4043 Alloy by Bilateral Friction Stir Post-processing

Authors：Bai, Xingwang^*; Wang, Yong; Lv, Hao; Zhang, Haiou; Zhou, Xiangman

Source：JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE, 2023.

DOI：10.1007/s11665-023-09047-1

• friction stir post-processing
• mechanical properties
• microstructure evolution
• wire arc additive manufacturing

To expand the application of aluminum alloy parts fabricated by wire arc additive manufacturing (WAAM) in industries, it is crucial to reduce porosity and refine the microstructure to improve mechanical properties as pores and non-uniform microstructure are major defects. In this study, bilateral friction stir post-processing (B-FSP) was used as post-processing to the parts made by WAAM. The microstructural evolution after B-FSP deformation and the strengthening mechanisms were investigated. As compared to the conventional WAAM processing of Al-Si alloy, it was found that the introduction of B-FSP and U-FSP can effectively eliminate the pores, and both the alpha-Al dendrites and Si-rich eutectic network were severely broken up, leading to a remarkable enhancement in ductility. The WAAM parts after B-FSP exhibit an average yield strength of 78.18 MPa, an ultimate tensile strength of 135 MPa, an average hardness of 48 HV, and vertical and horizontal elongation (EL) of 28.7 and 38.4%, respectively. The anisotropy caused by non-uniform stirring is responsible for the difference in EL. Notably, unilateral friction stir post-processing (U-FSP) results in a 12.5% increase in hardness and a 65.5% increase in EL, while bilateral FSP yields a 20% increase in hardness and a 72.2% increase in El compared to plain WAAM parts. These findings provide a strong foundation and strategy for enhancing ductility, hardness, reducing porosity, and refining the microstructure of the additively manufactured aluminum alloy components.

• Institution
  华中科技大学