S. Liu, C. Li, X. Jin, D. Ma, Q. Yan, G. Liu, J. Liu, X. Cao, H. Wang
International Journal of Mechanical Sciences 285 (2025) 109822

Abstract. Surface post-processing of metal additive manufacturing components is challenging due to their typically complex geometries (e.g., curved surfaces) coupled with high initial surface roughness. Herein, we propose an efficient solid dielectric electrochemical polishing (SDECP) method employing ion exchange resin particles with a porous structure that absorbs and stores electrolytes as a conductive medium. This method enhances the surface quality of additively manufactured components with Bézier curved surfaces to a mirror finish, achieving improvements in Sa, Sq, and Sz of 91.5%, 91.7%, and 86.9%, respectively. Planetary motion strategies are implemented to optimize mass transfer on the anode surface in the discontinuous solid dielectric. Results indicate that bidirectional planetary motion (BPR) in SDECP effectively improves the uniformity of surface roughness and material removal across different regions of the part. Furthermore, we quantitatively describe the relationship between material removal rate (MRR) and average current in SDECP. The intermittent material removal mechanism of SDECP is elucidated utilizing discrete element method (DEM) simulations. Our work offers innovative insights into the material removal mechanisms of SDECP, presenting an efficient approach for overall surface post-processing of metal additive manufacturing component.

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This work was supported by the National Natural Science Foundation of China [grant numbers 52375402, 52205439], China Space Foundation Aerospace Propulsion Public Welfare Special Fund [grant number KDJJ20230502014], China Scholarship Council (grant number 202306030013), Fundamental Research Funds for the Central Universities of China (NG2024006), and Singapore Ministry of Education Academic Research Funds (A-8001225-00-00).

Z. Zhang, Y.J. Lee, Q. Yan, H. Wang, Z. Tong, X. Jiang
Tribology International 202 (2025) 110341

Abstract. The nanoscratch test, as an established technique for assessing material tribological properties has received significant attention. However, the symmetry and anisotropy in scratching performances as well as the quantitative correlation between the orientation-dependent deformation and inherent microscopic deformation mechanism remain unexplored. Herein, crystal plasticity simulations can quantitatively capture scratching forces, elastic recovery, and surface pile-ups, as well as accurately describe inner deformation fields and lattice rotation patterns, as confirmed by experimental results. The simulation results reveal that surface pile-up and elastic recovery mappings on (001)-, (011)-, and (111)-oriented samples exhibit eight-fold, four-fold, and six-fold symmetries, respectively. The orientation-dependent location and intension of both slip activities and lattice rotation, determine the features of macroscopic elastoplastic deformation under scratching.

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Supported by Ministry of Education, Singapore, Academic Research Funds (Grant Nos.: A-8001225–00-00 and MOET2EP50220–0010).