Hostname: page-component-cd9895bd7-dk4vv Total loading time: 0 Render date: 2024-12-28T00:40:18.302Z Has data issue: false hasContentIssue false
  • English
  • Français

Solute concentration dependence of strength and plastic instabilities in Al-Mg alloys

Published online by Cambridge University Press:  03 March 2011

Gy. Horváth ,
N.Q. Chinh  and
J. Lendvai
Gy. Horváth
Affiliation:
Department of General Physics, Eötvös University, 1117 Budapest, Hungary
N.Q. Chinh*
Affiliation:
Department of General Physics, Eötvös University, 1117 Budapest, Hungary
J. Lendvai
Affiliation:
Department of General Physics, Eötvös University, 1117 Budapest, Hungary
*
a) Address all correspondence to this author. e-mail: chinh@metal.elte.hu
Get access

Abstract

Characteristics of the dynamic strain aging (DSA) in the Portevin-Le Chatelier effect are experimentally investigated by dynamic indentation tests and numerically analyzed by using literature models. Experimental results obtained on Al–Mg alloys show that the occurrence and development of the plastic instabilities—serrated indentation—depend strongly on the solute content. During dynamic microindentation tests the amplitude of microhardness drops—similarly to the global hardness—and is changing as a power law function of Mg solute content with an exponent of 2/3. It has been shown that the term describing the effect of DSA in serrated flow is not proportional but rather a power expression of the local solute concentration, Cs, on the dislocation line with the exponent of 1/2. Together with this, the kinetics of solute segregation during DSA is controlled by the pipe diffusion.

Keywords

HardnessIndentationMechanical properties
Type
Articles
Information
Journal of Materials Research , Volume 20 , Issue 2 , February 2005 , pp. 331 - 337
Copyright
Copyright © Materials Research Society 2005

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.Schwink, Ch. and Nortmann, A.: The present experimental knowledge of dynamic strain ageing in binary f.c.c. solid solutions. Mater. Sci. Eng. A 234–236, 1 (1997).CrossRefGoogle Scholar
2.Zaiser, M. and Hähner, P.: Oscillatory modes of plastic deformation: Theoretical concepts. Phys. Stat. Sol. 199, 267 (1997).3.0.CO;2-Q>CrossRefGoogle Scholar
3.Thevenet, D., Mliha-Touati, M. and Zeghloul, A.: The effect of precipitation on the Portevin-Le Chatelier effect in an Al–Zn– Mg–Cu alloy. Mater. Sci. Eng. A 266, 175 (1999).CrossRefGoogle Scholar
4.Pink, E. and Grinberg, A.: Stress drops in serrated flow curves of A15Mg. Acta Metall. 30, 2153 (1982).CrossRefGoogle Scholar
5.McCormick, P.G., Venkadesan, S. and Ling, C.P.: Propagative instabilities: An experimental view. Scripta Metall. Mater. 29, 1159 (1993).CrossRefGoogle Scholar
6.Kovács, Zs., Lendvai, J. and Vörös, G.: Localized deformation bands in Portevin-Le Châtelier plastic instabilities at a constant stress rate. Mater. Sci. Eng. A 279, 179 (2000).CrossRefGoogle Scholar
7.McCormick, P.G.: The Portevin-Le Chatelier effect in an Al-Mg-Si alloy loaded in torsion. Acta Metall. 30, 2079 (1982).CrossRefGoogle Scholar
8.Kovács, Zs., Chinh, N.Q., Lendvai, J. and Vörös, G.: PortevinLe Châtelier type plastic instabilities in depth sensing macro-indentation. Mater. Sci. Eng. A 325, 255 (2002).Google Scholar
9.Bérces, G., Chinh, N.Q., Juhász, A. and Lendvai, J.: Occurrence of plastic instabilities in dynamic microhardness testing. J. Mater. Res. 13, 1411 (1998).CrossRefGoogle Scholar
10.Bérces, G., Chinh, N.Q., Juhász, A. and Lendvai, J.: Kinematic analysis of plastic instabilities occurring in microhardness tests. Acta Mater. 46, 2029 (1998).CrossRefGoogle Scholar
11.Chinh, N.Q., Csikor, F., Kovács, Zs. and Lendvai, J.: Critical concentration of Mg addition for plastic instabilities in Al–Mg alloys. J. Mater. Res. 15, 1037 (2000).Google Scholar
12.Chinh, N.Q., Horváth, Gy., Kovács, Zs. and Lendvai, J.: Characterization of plastic instability steps occurring in depth-sensing indentation tests. Mater. Sci. Eng. A 324, 219 (2002).CrossRefGoogle Scholar
13.Bérces, Gy., Lendvai, J., Juhász, A. and Chinh, N.Q.: Dynamic characterization of Portevin-Le Chatelier instabilities occurring in depth-sensing microhardness tests. J. Mater. Res. 18, 2874 (2003).Google Scholar
14.Chinh, N.Q., Gubicza, J., Kovács, Zs. and Lendvai, J.: Depth-sensing indentation tests in studying plastic instabilities. J. Mater. Res. 19, 31 (2004).Google Scholar
15.Golovin, Y.M., Ivolgin, V.I., Lebedkin, M.A. and Sergunin, D.A.: Rate and scale dependence of the parameters of the unstable plastic flow during dynamic nano- and microindentation of an Al-2.7% Mg alloy. Phys. Met. Metall. 97, 220 (2004).Google Scholar
16.van den Beukel, A.: Theory of the effect of dynamic strain ageing on mechanical properties. Phys. Stat. Sol. (a) 30, 197 (1975).CrossRefGoogle Scholar
17.Penning, P.: Mathematics of the Portevin-le Chatelier effect. Acta Metall. 20, 1169 (1972).CrossRefGoogle Scholar
18.Kubin, L.P. and Estrin, Y.: The Portevin-Le Chatelier effect in deformation with constant stress rate. Acta Metall. 33, 397 (1985).CrossRefGoogle Scholar
19.Kubin, L.P., Chibab, K. and Estrin, Y.: The rate dependence of the Portevin-Le Chatelier effect. Acta Metall. 36, 2707 (1988).Google Scholar
20.Kubin, L.P. and Estrin, Y.: Evolution of dislocation densities and the critical conditions for the Portevin-Le Châtelier effect. Acta Metall. Mater. 38, 697 (1990).CrossRefGoogle Scholar
21.Brechet, Y. and Estrin, Y.: On the influence of precipitation on the Portevin-Le Chatelier effect. Acta Metall. Mater. 43, 955 (1995).CrossRefGoogle Scholar
22.McCormick, P.G.: Theory of flow localization due to dynamic strain ageing. Acta Metall. 36, 3061 (1988).CrossRefGoogle Scholar
23.Cottrell, A.H.: A note on the Portevin-Le Chatelier effect. Philos. Mag. 44, 829 (1953).CrossRefGoogle Scholar
24.McCormick, P.G.: A model for the Portevin-Le Chatelier effect in substitutional alloys. Acta Metall. 20, 351 (1972).CrossRefGoogle Scholar
25.Louat, N.: On the theory of the Portevin-Le Chatelier effect. Scripta Metall. 15, 1167 (1981).Google Scholar
26.Louat, N.: On the thermal activation of dislocation motion through random point obstacles. Acta Metall. 26, 1597 (1978).Google Scholar
27.Lebyodkin, M., Brechet, Y., Estrin, Y. and Kubin, L.: Statistical behavior and strain localization patterns in the Portevin-Le Chatelier effect. Acta. Mater. 44, 4531 (1996).CrossRefGoogle Scholar
28.Hähner, P.: On the critical conditions of the Portevin–Le Châtelier effect. Acta Mater. 45, 3695 (1997).CrossRefGoogle Scholar
29.Hähner, P.: On the physics of the Portevin-Le Châtelier effect part 1: The statistics of dynamic strain ageing. Mater. Sci. Eng. A 207, 208 (1996).Google Scholar
30.Hähner, P.: On the physics of the Portevin-Le Châtelier effect part 1: From microscopic to macroscopic behavior. Mater. Sci. Eng. A 207, 216 (1996).Google Scholar
31.Springer, F. and Schwink, Ch.: Quantitative investigations on dynamic strain ageing in polycrystalline CuMn alloys. Scripta Metall. Mater. 25, 2739 (1991).Google Scholar
32.Ling, C.P. and McCormick, P.G.: The effect of temperature on strain rate sensitivity in an Al–Mg–Si alloy. Acta Metall. Mater. 41, 3127 (1993).Google Scholar
33.Labusch, R.: Statistical theories of solid solution hardening. Acta Metall. 20, 917 (1972).CrossRefGoogle Scholar
34.Nabarro, F.R.N.: Theory of solution hardening. Philos. Mag. 35, 613 (1977).CrossRefGoogle Scholar
35.Friedel, J.: Dislocations (Pergamon Press, New York, 1964), p. 644.Google Scholar
36.Tabor, D.: Indentation hardness and its measurement: Some cautionary comments, in Microindentation Techniques in Materials Science and Engineering (ASTM STP 889, 1986) p. 129.Google Scholar
37.Klose, F.B., Ziegenbein, A., Hagemann, F., Neuhäuser, H., Hähner, P., Abbadi, M. and Zeghloul, A.: Analysis of Portevin-Le Chatelier serrations of type B in Al-Mg. Mater. Sci. Eng. A 369, 76 (2004).CrossRefGoogle Scholar
38.Picu, R.C.: A mechanism for the negative strain-rate sensitivity of dilute solid solutions. Acta Mater. 52, 3447 (2004).Google Scholar
39.Picu, R.C. and Zhang, D.: Atomistic study of pipe diffusion in Al–Mg alloys. Acta Mater. 52, 161 (2004).CrossRefGoogle Scholar