Abstract
An alternative indentation method to study materials that present a time-dependent behaviour (e. g. viscoelasticity) is the dynamic stiffness measurement technique, which provides fast and accurate values of the elastic properties through the calculation of the storage modulus (related to the elastic recovery of the material), and the loss modulus (related to the damping), using indentation cycles with oscillating load or displacement. We have made dynamic measurements on four amorphous materials (CNx, amorphous carbon, fused silica and polypropylene). Such materials have a relatively low density compared to crystalline materials of similar composition and atoms are able to move into internal free space during deformation. The results suggest that all the amorphous materials have a similar time-dependant behaviour associated with the restrictions to movement of atoms (or chains) by neighbouring atoms in the amorphous structure.
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The work was supported in part by the European Community’s Human Potential programme under contract HPRN-CT-2002-00209 (Fullmat). J. F. P. acknowledges financial support from the programme.
References
[1] J.B. Pethica, R.B. Hutchings, W.C. Oliver: Phil. Mag. A 48 (1983) 593.10.1080/01418618308234914Search in Google Scholar
[2] W.C. Oliver, G.M. Pharr: J. Mater. Res. 7 (1992) 1564.10.1557/JMR.1992.1564Search in Google Scholar
[3] S.V. Hainsworth, H.W. Chandler, T.F. Page: J. Mater. Res. 11(1996) 1987.10.1557/JMR.1996.0250Search in Google Scholar
[4] J. Malzbender, G. deWith, J. den Toonder: J. Mater. Res. 15 (2000)1209.10.1557/JMR.2000.0171Search in Google Scholar
[5] W.C. Oliver: J. Mater. Res. 16 (2001) 3202.10.1557/JMR.2001.0441Search in Google Scholar
[6] X. Li, B. Bhushan: Mater. Charact. 48 (2002) 11.10.1016/S1044-5803(02)00192-4Search in Google Scholar
[7] S.A. Syed Asif, K.J. Wahl, R.J. Colton: Rev. Sci. Instr. 70 (1999) 2408.10.1063/1.1149769Search in Google Scholar
[8] H. Sjöström, L. Hultman, J.-E. Sundgren, S.V. Hainsworth, T.F. Page, G.S.A.M. Theunisen: J. Vac. Sci. Technol. A 14 (1996) 56.10.1116/1.579880Search in Google Scholar
[9] N. Hellgren, M.P. Johanson, E. Broitman, L. Hultman, J.-E. Sundgren: Phys. Rev. B 59 (1999) 5162.10.1103/PhysRevB.59.5162Search in Google Scholar
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