Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-23T19:13:14.475Z Has data issue: false hasContentIssue false
  • English
  • Français

Occurrence of plastic instabilities in dynamic microhardness testing

Published online by Cambridge University Press:  31 January 2011

G. Bérces ,
N. Q. Chinh ,
A. Juháasz  and
J. Lendvai
G. Bérces
Affiliation:
Department of General Physics, Eötvös University, Budapest, H-1088 Múzeum krt. 6–8, Budapest, Hungary
N. Q. Chinh
Affiliation:
Department of General Physics, Eötvös University, Budapest, H-1088 Múzeum krt. 6–8, Budapest, Hungary
A. Juháasz
Affiliation:
Department of General Physics, Eötvös University, Budapest, H-1088 Múzeum krt. 6–8, Budapest, Hungary
J. Lendvai
Affiliation:
Department of General Physics, Eötvös University, Budapest, H-1088 Múzeum krt. 6–8, Budapest, Hungary
Get access

Abstract

Plastic instabilities were observed to appear during dynamic ultramicrohardness testing of a solid solution Al–3.3 wt.% Mg alloy. The tests were carried out at room temperature with a Vickers hardness indenter in a computer-controlled dynamic ultramicrohardness testing machine. During the tests the applied load was increased from 0 to 2000 mN at constant loading rate. The instabilities appear as characteristic steps in the continuously recorded load-indentation depth curves. The physical basis for the occurrence of the instabilities is the interaction between moving dislocations and solute atoms, a phenomenon termed in the literature as serrated yielding, jerky flow, or Portevin-Le Châtelier effect. The instabilities start at a critical load, Fc, in the depth-load curve. Varying the loading rate, μ, by two orders of magnitude Fc was found to increase linearly with the loading rate.

Type
Articles
Information
Journal of Materials Research , Volume 13 , Issue 6 , June 1998 , pp. 1411 - 1413
Copyright
Copyright © Materials Research Society 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Neuhäuser, H. and Schwink, C., in Materials Science and Technology, edited by Cahn, R. W., Haasen, P., and Kramer, E. J., Vol. 6, edited by H. Mughrabi (VCH, Weinheim, Germany, 1993), p. 191.Google Scholar
2.Brechet, Y. J. M., in Nonequilibrium Materials, edited by Lendvai, J., Key Engineering Materials, Vol. 103 (Trans Tech Publications, Switzerland, 1995), p. 21.Google Scholar
3.McCormick, P. G., Scripta Metall. 15, 441 (1982).CrossRefGoogle Scholar
4.Brindley, B. J. and Worthington, P. J., Scripta Metall. 17, 1357 (1969).Google Scholar
5.Pink, E. and Grinberg, A., Mater. Sci. Engng. 51, 1 (1981).CrossRefGoogle Scholar
6.Schaarwächter, W. and Ebener, H., Acta Metall. Mater. 38, 195 (1990).CrossRefGoogle Scholar
7.Tabor, D., The Hardness of Metals (Clarendon Press, Oxford, 1951).Google Scholar
8.Bérces, G., Chinh, N. Q., Juhász, A., and Lendvai, J., Acta Mat. (in press).Google Scholar