Lu, NanshuWang, XiSuo, ZhigangVlassak, Joost2010-07-082009Lu, Nanshu, Xi Wang, Zhigang Suo, and Joost Vlassak. 2009. Failure by simultaneous grain growth, strain localization, and interface debonding in metal films on polymer substrates. Journal of Materials Research 24(2): 379-385.0884-2914http://nrs.harvard.edu/urn-3:HUL.InstRepos:4276342In a previous paper, we have demonstrated that a microcrystalline copper film well bonded to a polymer substrate can be stretched beyond 50% without cracking. The film eventually fails through the co-evolution of necking and debonding from the substrate. Here we report much lower strains to failure (around 10%) for polymer-supported nanocrystalline metal films, whose microstructure is revealed to be unstable under mechanical loading. We find that strain localization and deformation-associated grain growth facilitate each other, resulting in an unstable deformation process. Film/substrate delamination can be found wherever strain localization occurs. We therefore propose that three concomitant mechanisms are responsible for the failure of a plastically deformable but microstructurally unstable thin metal film: strain localization at large grains, deformation-induced grain growth and film debonding from the substrate.en-UScu filmsgrain growthstrain localizationdebondingKaptonJournal Article2010-07-0810.1557/JMR.2009.0048