Date:

2025-10-16

Title of Paper:

Non-equilibrium solidification complexions in additive manufacturing enable exceptional creep resistance: An example in nickel-based superalloys

Journal:

International Journal of Plasticity

Summary:

Insufficient time-dependent properties at elevated temperatures, particularly creep resistance and ductility, are currently crucial factors impeding the use of additively manufactured Hastelloy X (HX). To address this limitation, a micro-nano olive-shaped carbide network was purposely introduced into HX via laser powder bed fusion (L-PBF) and following optimized heat treatment. The inherent chemical heterogeneity combined with the sufficient stored energy of boundaries, induced by the ultrafast cooling rate of the L-PBF process, creates favorable conditions for the formation of micro-nano precipitate networks. Compared to its untreated counterpart, the optimized HX exhibited considerably improved creep resistance, with an 85% increase in creep life and a 122% improvement in fracture ductility. Furthermore, through multiscale characterization techniques and theoretical calculations, the preferential precipitation behavior of the micro-nano carbide networks was systematically investigated from both kinetic and thermodynamic perspectives. The superior creep resistance of the L-PBF HX, decorated with carbide networks, stems from the synergistic effects of the high cavity surface energy, effective pinning for grain boundary sliding, and reduced plasticity-assisted diffusion rate, which markedly inhibit the nucleation and growth of microvoids during high-temperature deformations. This work provides a comprehensive understanding of the strengthening mechanisms associated with non-equilibrium solidification-facilitated carbide networks, providing new insights into the targeted design and optimization of L-PBF alloys.

Co-author:

Y.S. Li, L.Q. Cui, J.H. Xu, T.Z. Xin, S. Jiang, Y. Li, H.H. Zhang, X.F. Dang, S. Gao, Y.H. Mu, K.J. Lu, J. Moverare, W.F. He

Volume:

205

Page Number:

102345

Translation or Not:

No

Date of Publication:

2025-06-03