Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10668172 | Surface and Coatings Technology | 2011 | 6 Pages |
Abstract
Nano-indentation, nano-scratch and nano-fretting tests were performed on highly polished Si(100) using a commercial ultra-low drift nano-mechanical test system (NanoTest, Micro Materials Ltd.) fitted with a 4.6 μm sphero-conical diamond indenter. In addition to plastic deformation, the contact deformation of Silicon is strongly affected by phase transformation and micro-/nano-fracture at room temperature. The objective of this work was to investigate the influence of tangential loading by comparison of deformation in the idealised loading in the nano-indentation test with the more complex tribo-contact situations. A novel method is introduced allowing quantitative comparison of deformation during loading in the nano-indentation, nano-scratch and nano-fretting tests. The loading curves in all three tests were almost identical at very low load. Tangential loading in the nano-scratch and nano-fretting tests promotes yield resulting in greater penetration depths at higher load than in nano-indentation. Contact damage assessment by in situ measurements of probe displacement during nano-fretting was supported by post-test SEM imaging and wear scar measurement by confocal microscopy. The nano-fretting crack morphology was related to the normal load applied and resulting track length. A brittle/ductile response of the material was observed, characterised by brittle micro-chips around wear track and ductile wear debris observed in the centre of the contact. The critical loads in the nano-scratch test show a subtle dependence on scan speed and loading rate. Pronounced lateral cracking observed in high load nano-scratch and nano-indentation tests is absent in the nano-fretting tests, which is consistent with the fretting wear process minimising the accumulation of strain.
Keywords
Related Topics
Physical Sciences and Engineering
Materials Science
Nanotechnology
Authors
B.D. Beake, T.W. Liskiewicz, J.F. Smith,