Improving ductility of Al0.74Mo0.26 alloy films through synergy of phase fraction and morphology of nanocrystallites dispersed in amorphous matrix

Amorphous alloy films exhibit high strength but low ductility, which limits their structural performance appli-cations. Herein, we synthesize dual-phase composite Al0.74Mo0.26 alloy films via the introduction of nano crystallites to amorphous matrix through changing the deposition rate of magnetron sputtering, which can significantly improve the ductility of amorphous alloy film. It has been found that the ductility of composite films are controlled by synergy of phase fraction and morphology of the nanocrystallite, rather than the monotonous increase as a function of nanocrystallite phase fraction. Among them, the composite film composed of a phase fraction with 48% equiaxed-nanocrystallite dispersed in amorphous matrix, displays extremely excellent ductility with critical strain (epsilon(C)) as high as 2.83%, which is approx. 3 times that of amorphous alloy film. Then, the synergy of phase fraction and morphology of nanocrystallite on improving ductility of composite films is discussed systematically from the perspective of crack nucleation and propagation. Furthermore, elastic modulus, hardness and strength of the composite films are also investigated in order to characterize the mechanical properties of composite films, and provide reference for their application.

Automated summary

By introducing nano crystallites to amorphous matrix through changing the deposition rate of magnetron sputtering, dual-phase composite Al0.74Mo0.26 alloy films with significantly improved ductility can be synthesized. The ductility of composite films is determined by the synergy of phase fraction and morphology of nanocrystallite, rather than a monotonous increase with nanocrystallite phase fraction.