Adaptive strengthening of AlNiCe amorphous thin films under space cryogenic thermal cycling

Amorphous alloys provide promising protection for polymers used in spacecraft. The study systematically investigates the microstructure and service performance of AlNiCe amorphous thin films (ATFs) under cryogenic thermal cycling (CTC) in the low Earth orbit. AlNiCe ATFs preserve disordered nature while exhibiting a distinct non-monotonic mechanical evolution in surface modulus and energy dissipation with prolonged CTC. Besides, variations in the correlation length of phase shift further capture the dynamic evolution of structural heterogeneity, which is correlated with energy state. Moreover, combined with relaxation time spectra extracted from creep behaviors, AlNiCe ATFs experience the dynamic structural transitions from initial rejuvenation to subsequent relaxation. The microscopic inversion originates from transitions in atomic dynamics accompanied by the evolution of the local ordering degree. Initially, the generation and interconnection of loosely packed domains are driven by non-affine thermal strain, while the generation of more densely packed configuration is facilitated by cumulative thermal input after prolonged CTC. Notably, a limited number of crystal-like ordered clusters precipitate within amorphous matrix after prolonged CTC, further reinforcing the dynamic load-bearing capability and creep resistance. The preserved microstructural stability and enhanced performance highlight the potential of AlNiCe ATFs as protective coatings in the space environment.