Sample size effect on nanoindentation of micro-/nanostructures

The sample size effect on nanoindentation of micro-/nanostructures was studied by the finite element analysis method. It was found that a significant sample size effect occurs when the sample size is comparable to the indent size. To avoid the sample size effect on mechanical property measurements of micro-/nanostructures, nanoindentation must be done within a certain critical indent size to sample size ratio. The nanoindentation testing criteria for micro-/nanostructures have been established. The indentation deformation behavior of soft and hard micro-/nanostructures is discussed in conjunction with the material properties, sample shape, and three-dimensional geometry length scale.