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Abstract

The paper considers the deformation processes involved in the nucleation and propagation of cracks in high-strength Al-Zn-Mg alloys, when tested in tension, and examines the influence of microstructure on these processes. For a superpure alloy, the effects on tensile properties of the width of the precipitate-free zone adjacent to grain boundaries and of the grain-boundary-precipitate characteristics have been determined. Tensile properties of superpure and commercial alloys are compared—the commercial alloy, tested in the ‘longitudinal’ direction, is more ductile for the same heat-treatment. A mechanism of fracture is proposed that explains the observed results. Several points of disagreement with earlier proposed deformation and fracture mechanisms are noted and discussed.

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References

Geissler

A. H.

, Trans. Met. Soc. AIME, 1964, 180, 245.

Varley

P. C.

, Day

M. K. B.

, and Sendorek

, J. Inst. Metals, 1957–58, 86, 337.

Thomas

and Nutting

, ibid., 1959 –60, 88, 81.

Polmear

I. J.

, ibid., 1963 –64, 92, 153.

Unwin

P. T. N.

, Ph.D. Thesis, Cambridge Univ., 1968.

Unwin

P. T. N.

and Smith

G. C.

, J. Inst. Metals, 1969, 97, 299.

Ryum

, Ada Met., 1968, 16, 327.

Ryum

, ibid., 1969, 17, 821.

Ryder

D. A.

and Smale

R. C.

, ‘Fracture of Solids’ (edited by Drucker

D. C.

and Gilman

J. J.

) 237. 1963: New York and London

(Interscience Publishers).

10.

Ryum

and Baardseth

, J. Inst. Metals, 1968, 96, 92.

11.

Cornish

A. J.

and Day

M. K. B.

, ibid., 1971, 99, 377.

12.

Hunter

M. S.

and McMillan

J. C.

, ‘Electron Fractography’ (Special Tech. Publ. No. 436), p. 196. 1968: Philadelphia, Pa. (Amer. Soc. Test. Mat).

13.

Kirman

. Met. Trans., 1971, 2, 1761.

14.

Piper

D. E.

, Quist

W. E.

, and Anderson

W. E.

, ‘Application of Fracture Toughness Parameters to Structural Metals’, (edited by Greenberg

H. D.

), p. 227. 1966: New York

(Gordon and Breach).

15.

Embury

J. D.

and Nicholson

R. B.

, Acta Met., 1965, 13, 403.

16.

Lorimer

G. W.

and Nicholson

R. B.

, ibid., 1966, 14, 1009.

17.

Unwin

P. T. N.

, Lorimer

G. W.

, and Nicholson

R. B.

, ibid., 1969, 17, 1363.

18.

Unwin

P. T. N.

and Nicholson

R. B.

, ibid., p. 1379.

19.

Holl

H. A.

, Corrosion, 1967, 23, 173.

20.

Speidel

M. O.

, Physica Status Solidi, 1967, 22, (2), K71.

21.

Lynch

S. P.

, to be published.

22.

Rogers

H. C.

, Trans. Met. Soc. AIME, 1960, 218, 498.

Tensile Deformation and Fracture in High-Strength Al-Zn-Mg Alloys

Abstract

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References