Tensile Properties of Free-Standing Aluminum Thin Films
David T. Read, Yi-Wen Cheng, R R. Keller, Joseph D. McColskey
Tensile properties of electron-beam-deposited free-standing aluminum thin films were measured. High ςy and UTS were observed, mainly due to fine grain sizes, consistent with values reported in the literature. The observed Young's modulus, as measured by unloading-reloading experiments, was lower than half of the reported value for pure aluminum in the bulk form. Although other investigators have also observed the same low values, explanations of the decrease in modulus for the thin films are still lacking. The high ductility in terms of large % elongation observed in this investigation is attributed mainly to the high strain-rate sensitivity of the thin films. Calculations based on TEM observations suggest that the observed large plastic strains in the tensile tests are accumulated largely by slip.