TEM study of the deformation structures around nano-scratches

Abstract

An in-plane transmission electron microscopy (TEM) investigation carried out on nano-scratches made in a Ni₃Al foil revealed a high dislocation density within the scratch core, resulting in severe crystal rotations. The amount and sense of rotation were found to be asymmetrical about the longitudinal centre line of the scratch. Cross-sectional TEM analysis revealed that almost all the dislocations were confined within a semicircular zone having a radius similar to the calculated tip-sample contact size during scratching, in agreement with the in-plane TEM observations.

Keywords:

• nano-scratch
• focused ion-beam milling
• nanoidentation
• TEM
• dislocations

Acknowledgements

The work described in this paper was supported by a grant from the Research Grants Council of the Hong Kong Special Administration Region, P.R. China (Project No. HKU7162/06E), as well as a grant from the University of Hong Kong (no. 10206180). The authors wish to thank Prof. S.G. Roberts for his very useful comments on an earlier draft and IPJ would like to thank the Department of Mechanical Engineering for its hospitality during two visits.