[Introduction]Thin films grown on polycrystalline substrates in the form of three-dimensional island have a gradient in growth stress along the thickness direction,which significantly affects the initiation and propagation of cracks within the films.[Method]The relationship between the stress gradient and cracking behavior of brass film was established by observing the evolution of crack morphology during the electrodeposition of brass film and conducting the in-situ measurement of growth stress.[Result]The crack pattern of brass film was greatly affected by its growth stress during electrodeposition.The presence of compressive stress could inhibit the cracking of the film at initial growth stage.While the tensile stress caused by the contact of island-like structures promoted the formation of cracks on film surface,which was more likely to occur at the boundaries of adjacent island-like structures.With the extending of electrodeposition time,cracks on film surface gradually propagated inwards due to the increasing of growth stress.The compressive stress at later stage induced a change in the crack pattern from V-shape to O-shape.[Conclusion]The findings of this study can provide a theoretical basis for the fabrication of new types of films with low cracking sensitivity.
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