Haasen plot analysis of the HallPetch effect in Cu/Nb nanolayer composites Academic Article uri icon

abstract

  • We investigate the effects of layer thickness (t) on hardness (H) and rate sensitivity of the hardness (H/ ln ) in 1 m-thick Cu/Nb nanolayer composites. For t < 10 nm, we find that H correlates with t according to H = H0 = H1t-1/2, suggestive of a HallPetch mechanism with layer interfaces replacing grain boundaries as barriers against dislocation motion. The measured levels of H/ ln clearly indicate the operation of bulk-like dislocation mechanisms consistent with a HallPetch mechanism. However, based on a Haasen-plot activation analysis, it appears that the HallPetch coefficient, H1, is strongly rate-dependent, inconsistent with a conventional HallPetch mechanism. For specimens with t < 10 nm there is a saturation in hardness, but the rate sensitivity data indicate no clear evidence of a corresponding change in mechanism. Simple models are proposed.

published proceedings

  • Journal of Materials Research

author list (cited authors)

  • Tambwe, M. F., Stone, D. S., Griffin, A. J., Kung, H., Cheng, Y., & Nastasi, M.

citation count

  • 32

complete list of authors

  • Tambwe, MF||Stone, DS||Griffin, AJ||Kung, H||Cheng, Y||Nastasi, M

publication date

  • February 1999