Anisotropy and Stress-State-Dependent Fracture in Additively Manufactured Metals

Abstract:

Despite remarkable advances in additive manufacturing (AM), the uncertainty in direction-dependent strength and fracture behavior of metallic components still poses major challenges for their reliable structural application. The layered nature of laser powder bed fusion (LPBF) produces highly anisotropic textures and microstructure architectures that influence both plastic flow and fracture. While numerous studies have characterized tensile anisotropy, the coupling between build-induced anisotropy and stress-state-dependent fracture remains largely unresolved, yet it governs the structural integrity of AM parts under multi-axial loading. In particular, the extent to which anisotropy alters the ductile-to-brittle transition or fracture locus is still unknown. This study addresses this gap by combining experiments and advanced constitutive fracture modelling for two typical AM metals, austenitic 316L stainless steel and AlSi10Mg aluminum alloy. The goal is to formulate a unified, physically based description of anisotropic plasticity and fracture that is applicable across various material classes. LPBF samples of 316L stainless steel and AlSi10Mg were built at multiple orientations between 0° and 90° relative to the build direction. Uniaxial tensile tests were carried out with digital image correlation to capture full-field strain evolution and to determine r-values as a measure of plastic anisotropy. Complementary fracture tests under different stress states ranging from simple shear to plane strain tension were designed to evaluate the fracture dependence on stress states and anisotropy. It can be concluded that both alloys exhibit orientation-dependent flow and r-value during plastic deformation. The fracture strain decreases with rising triaxiality, yet its rate of decrease depends strongly on orientation, demonstrating a clear coupling between anisotropy and stress state.

• Periodical: Key Engineering Materials (Volume 1047)
• Pages: 325-331
• Online since: April 2026
• Authors: Ehsan Amini, Guijia Li, Sven Bossuyt, Junhe Lian*
• Keywords: Additive Manufacturing, Anisotropy, Ductile Fracture, LPBF, Stress Triaxiality

References

[1] A. Fedorenko, B. Fedulov, Y. Kuzminova, S. Evlashin, O. Staroverov, M. Tretyakov, E. Lomakin, I. Akhatov, Anisotropy of Mechanical Properties and Residual Stress in Additively Manufactured 316L Specimens, Materials 14(23) (2021) 7176.

DOI: 10.3390/ma14237176

[2] A. Argyrou, L. Gargalis, L. Karavias, E.K. Karaxi, E.P. Koumoulos, Multi-Scale Mechanical Anisotropy and Heat Treatment Effects in Additively Manufactured AlSi10Mg, Metals 15(8) (2025) 890.

DOI: 10.3390/met15080890

[3] Z. Li, F. Shen, Y. Liu, C. Hartmann, R. Norz, S. Münstermann, W. Volk, J. Min, J. Lian, Anisotropic fracture behavior of the 3rd generation advanced high-strength – Quenching and Partitioning steels: Experiments and simulation, J. Mater. Res. Technol. 30 (2024) 9395–9414.

DOI: 10.1016/j.jmrt.2024.05.228

[4] R. Juan, J. Lian, Failure mechanisms in quenching and partitioning (Q&P) steel under varying stress states, J. Mater. Sci. Technol. 263 (2026) 175–188.

DOI: 10.1016/j.jmst.2025.09.010

[5] S. Yang, Y. Zhang, R. Juan, Z. Li, J. Wu, S.O. Akinwamide, J. Kuva, R.V. Björkstrand, J. Lian, Effect of building orientation, thickness, and contouring on the microstructure and mechanical properties of AlSi10Mg via laser powder bed fusion, Mater. Sci. Eng., A 923 (2025) 147685.

DOI: 10.1016/j.msea.2024.147685

[6] A.E. Tekkaya, P.O. Bouchard, S. Bruschi, C.C. Tasan, Damage in metal forming, CIRP Ann. 69(2) (2020) 600–623.

DOI: 10.1016/j.cirp.2020.05.005

[7] A. Pineau, A.A. Benzerga, T. Pardoen, Failure of metals I: Brittle and ductile fracture, Acta Mater. 107 (2016) 424–483.

DOI: 10.1016/j.actamat.2015.12.034

[8] P.J. Noell, J.D. Carroll, B.L. Boyce, The mechanisms of ductile rupture, Acta Mater. 161 (2018) 83–98.

DOI: 10.1016/j.actamat.2018.09.006