• Media type: E-Article
  • Title: Nanomechanical Testing for Fracture of Oxide Films
  • Contributor: Morasch, K.R.; Bahr, D.F.
  • Source: Journal of Materials Research ; 20 ( 2005 ) S. 1490-1497
  • Published: Cambridge University Press (CUP), 2005
  • Language: Englisch
  • DOI: 10.1557/jmr.2005.0188
  • ISSN: 0884-2914; 2044-5326
  • Keywords: Mechanical Engineering ; General Materials Science ; Mechanics of Materials ; Condensed Matter Physics
  • Abstract: <jats:p>The mechanical properties of thermally grown oxide films on various aluminum substrates were tested using nanoindentation. A sudden discontinuity, indicative of film fracture, was observed upon loading portion of the load–depth curve. The 63-nm-thick films were determined to have ultimate strengths between 4.8 and 8.9 GPa. The ultimate stress is a superposition of the bending and membrane stress. The stress intensity at fracture for each of the films was developed by approximating the resulting bending moment and various cracks sizes. At a constant ratio of crack size to oxide thickness of 0.3, the applied stress intensity at fracture of these aluminum oxide films were between 0.46 and 1.20 MPa m<jats:sup>1/2</jats:sup>. The residual stress in the film was assumed to be negligible in the stress intensity calculation.</jats:p>