Segregation-sandwiched stable interface suffocates nanoprecipitate coarsening to elevate creep resistance
Yihan Gao, Peng Guan, Rong Su, Hong‐Wu Chen, Chong Yang, Cong He, Lingfei Cao, Hui Song, Jinyu Zhang, Xuefeng Zhang, Gang Liu, Jian‐Feng Nie, Jun Sun, E. Ma
Abstract
We demonstrate a strategy to stabilize nanoprecipitates in Al–Cu alloys, based on computational design that identifies synergistic solutes (Sc and Fe) that simultaneously segregate to the θ′-Al2Cu/Al interface and strongly bond to one another. Furthermore, Sc and Fe are predicted to each segregate into a separate atomic plane, forming a sandwiched structure reinforcing the interface. This interfacial architecture was realized through a simple heat treatment in a Sc–Fe–Si triple-microalloyed Al–Cu model alloy. Such a back-to-back layered interface, thermodynamically stable and kinetically robust, is found to suffocate nanoprecipitate coarsening at 300°C, enabling a dramatic reduction in creep rate.IMPACT STATEMENTThe segregant architecture of synergistic solute at θ′-Al2Cu/Al interface was guided by computational calculations and artificially realized at atomic scale to achieve an ultra-high thermal stability of θ′-Al2Cu, leading to a high creep resistance at 300°C.