Journal Article

Mechanical field assisted additive manufacturing of ultrahigh strength aluminum alloy

Meng, Jinlong, Tan, Chaolin, Xiao, Jiafeng, Yin, Qianxing, Shen, Shengnan, Li, Hui, Du, Hejun, Liu, Wenjie

2025

Overview

Additive manufacturing of aluminum (Al) alloys has attracted significant attention in the aerospace industry. However, achieving ultrahigh-strength (>500 MPa) Al alloys remains challenging due to their intrinsic poor printability. Here, we report a novel hybrid additive manufacturing (HAM) approach to process ultrahigh-strength AlMgSc alloy, which combines laser powder bed fusion (LPBF) with interlayer ultrasonic shot peening (USP). The results show that the interlayer ultrasonic shot peening depth reached ∼700 µm, leading to almost full density and residual stress convection from tension to compression. The HAM method promotes equiaxed grain formation and refines grain due to grain recrystallizations. Interestingly, the HAM followed by aging treatment tailors the hierarchically multi-gradient structures, inhibits Mg element intragranular segregation, and promotes the multi-nanoprecipitates (e.g. Al 3 (Sc, Zr) and Al 6 Mn) precipitation. Remarkably, the HAM followed by aging treatment achieves yield strength of 609 MPa and breaks elongation of 7.5%, demonstrating ultrahigh strength and good ductility compared with other Al alloys manufactured by AM and forging as reported in the literature. The strength enhancement mechanisms in this AlMgSc alloy are discussed. The high-density Al 3 (Sc, Zr) precipitates are the main strengthening contributor, and unique hetero-deformation induced (HDI) strengthening (originates from the heterogeneous microstructures) further enhances the strength of the material. This work highlights a novel approach for processing complex-structured ultrahigh strength Al alloy components by hybrid additive manufacturing. Hybrid additive manufacturing for processing ultrahigh strength Al alloy. Hierarchically gradient microstructures involving grain and dislocation gradients. Achieved ultrahigh yield strength (>600 MPa) together with a good elongation of 7.5%. Hybrid additive manufacturing enhances strength without evidently sacrificing ductility.

• Publisher: IOP Publishing
• Subject: Additive manufacturing / Aerospace industry / Alloys / AlMgSc alloy / Aluminum / Aluminum base alloys / Density / dislocation evolution / gradient structures / hybrid additive manufacturing / Interlayers / mechanical properties / Powder beds / Precipitates / Residual stress / Scandium / Shot peening / Strengthening / Zirconium