Liu, Z. and Wang, J. and Sun, W. and Liu, X. and Gao, Z. and Li, J. and Zhan, X. (2025) Unveiling the dependence of mechanical properties and corrosion resistance on microstructural heterogeneity in additively manufactured 316L stainless steel. Journal of Materials Research and Technology, 37. pp. 4688-4707. ISSN 2238-7854
Full text not available from this repository.Abstract
Additive manufacturing (AM) offers significant advantages in geometric design flexibility due to its layer-by-layer printing process. Nevertheless, the inherent thermal cycling during AM can induce microstructural heterogeneity, which inevitably affects the mechanical properties and corrosion resistance of metallic components and may lead to unpredictable performance failures. In this study, distinct heterogeneous microstructures of 316L stainless steel (316L SS) were produced using four AM techniques: laser powder bed fusion (L-PBF), laser powder directed energy deposition (LP-DED), wire arc additive manufacturing (WAAM), and laser wire directed energy deposition (LW-DED). The relationships between microstructural heterogeneity and material properties were systematically investigated. Finite element simulations were performed to analyze the thermal cycles of each AM process, aiming to clarify the mechanisms behind the formation of different microstructures. It was observed that 316L SS fabricated by powder-based methods (L-PBF and LP-DED) exhibited unique features, including low δ-ferrite content and a high fraction of high-angle grain boundaries. These characteristics are attributed to the high cooling rates and steep thermal gradients involved in the cyclic thermal process, which enhance strength and ductility but reduce corrosion resistance. In contrast, 316L SS produced by wire-based methods (LW-DED and WAAM) demonstrated superior corrosion resistance. In particular, the microstructure of LW-DED 316L SS consisted of a high density of low-angle grain boundaries and distinct cellular δ-ferrite. These differences highlight the critical role of thermal history in governing microstructure evolution. This study underscores the importance of understanding microstructural heterogeneity in AM and provides valuable insights for the design and performance optimization of 316L SS components in practical applications.