Indentation scale dependence of tip-in creep behavior in Ni thin films

Nanoindentation creep tests have been performed under a constant rate P˙/P=0.1s-1 with the holding load ranging from 1000 to 9000 μN to investigate the dependence of indentation creep behavior of Ni films. The results show that the creep rate, creep stain rate, indentation stress and even stress exponents are all indentation depth dependent. Based on the experimental results, it is inferred that the creep is likely dominated by grain boundary sliding and a grain rotation mechanism for small indentation loads but by dislocation climb for large indents.