Effect of natural aging and preaging on subsequent precipitation process of an AI-Mg-Si alloy with high excess silicon

Abstract

The mechanism of the influence of natural aging (that occurs between solution heat treatment and artificial aging) and preaging immediately after quenching on the subsequent precipitation process in an AI-0.95Mg-1.55Si-0.3Mn-0.1Zr alloy was studied using differential scanning calorimetric analyses and microhardness measurements. The results show that natural aging has a distinct influence on the subsequent precipitation process. It is proposed that the formation of stable silicon clusters during natural aging is the major reason for such an effect. Preaging at 120 or 150°C for 5 min is effective in suppressing the clustering process, and thus inhibiting the deleterious effect of natural aging. The decrease in hardness due to the natural aging in the alloy studied is not as marked as that reported for balanced AI-Mg₂Si alloys. It is proposed that a high excess silicon content reduces the detrimental effect of natural aging.

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References

ARNOLD

S. A.

: JOM, 1993, 45, 12.

GUPTA

A. K.

, BURGER

G. B.

, JEFFREY

P. W.

, and LLOYD

D. J.

: in ‘Aluminum alloys: their physical and mechanical properties’, (ed. T. H. Sanders, Jr. and E. A. Starke, Jr), Vol. 3, 177; 1994, Atlanta, GA, Georgia Institute of Technology.

ANDERSEN

S. J.

: Metall. Mater. Trans A, 1995, 26A, 1931.

SAGALOWICZ

, HUG

, BECHET

, SAINFORT

, and LAPASSET

: in ‘Aluminium alloys: their physical and mechanical properties’ (ed. T. H. Sanders, Jr. and E. A. Starke, Jr), Vol. 1, 636; 1994, Atlanta, GA, Georgia Institute of Technology.

DUTTA

and ALLEN

S. AL

: J. Mater. Sci. Lett., 1991, 10, 323.

FEI

W. D.

and KANG

S. B.

: J. Mater. Sci. Lett., 1995, 14, 1795.

TAMIZIFAR

and LORIMER

G. W.

: in ‘3rd international conference on aluminium alloys: their physical and mechanical properties’, (ed. L. Arnberg etal.), Vol. 1, 220; 1992, Trondhiem, Norwegian Institute of Technology.

PASHLEY

D. W.

, JACOBS

M. G.

, and VEITZ

J. T.

, Philos. Mag., 1967, 16, 51.

FORTIN

P. E.

: Met. Prog., 1964, 86, 119.

10.

PASHLEY

D. W.

, RHODES

J. W.

, and SENDOREK

: J. Inst. Met., 1966, 94, 41.

11.

MURAKAMI

, KAWANO

, KOMATSU

, OHINISHI

, and NAKAZAWA

: Trans. Jpn Inst. Met., 1968, 9, 349.

12.

MOULIN

: in ‘Aluminum alloys: structure and properties’, (ed. Mondolfo

L. E.

), 796; 1976, London, Butterworths.

13.

ZHEN

, KANG

S. B.

, FEI

W. D.

, and KIM

H. W.

: J. Mater. Sci., 1997, 32, 1895.

14.

EDWARDS

G. A.

, DUNLOP

G. L.

, and COUPER

M. J.

: in ‘Aluminum alloys: their physical and mechanical properties’, (ed. Sanders

T. H.

Jr and Starke

E. A.

Jr ), Vol. 1, 620; 1994. Atlanta, GA, Georgia Institute of Technology.

15.

GUPTA

A. K.

and LLOYD

D. J.

: in ‘3rd international conference on aluminium alloys: their physical and mechanical properties’, (ed. L. Arnberg et al.), Vol. 2, 21; 1992, Trondhiem, Norwegian Institute of Technology.

16.

KOVACS

, LENDVAI

, and NAGY

: Acta Metall., 1972, 20, 975.