New perspective on slip band decohesion as unifying fracture event during fatigue crack growth in both small and long cracks

Abstract

Fractographic observations obtained from the aluminium alloy 2024-T351 form the basis for a qualitative model of fatigue crack growth which seeks to provide a unified understanding of crack initiation, small crack growth, and long crack growth from threshold to well advanced stage II growth. During this range of crack growth, it is deduced that plastic deformation at the crack tip can be localised by a three-dimensional array of intense slip bands. Decohesion at these slip band interfaces is viewed as being the underlying fracture event that leads to crack growth. This concept explains the observed crack path, is consistent with several basic features of fatigue crack growth, and links crack growth with an accepted model for crack initiation. It identifies a unit increment of crack growth and provides a source of damage for the process zone ahead of the crack tip. The concept is not material dependent, but does depend upon the concentration of slip into persistent slip bands. An effect of environment on crack growth is expected to follow from its effect on slip band decohesion.

Get full access to this article

View all access options for this article.

References

SURESH

: ‘Fatigue of materials’; 1991, Cambridge, Cambridge University Press.

SCHITVE

: JSME Int. J. I, 1991, 34, 269–280.

DAVIDSON

D. L.

and LANKFORD

: Mater. Rev., 1992, 37, 45–76.

McDOWELL

D. L.

: Int. J. Fract., 1996, 80, 103–145.

FORSYTH

P. J. E.

: Acta Metall., 1963, 11, 703–715.

KNOTT

J. F.

: in ‘Fatigue crack growth — 30 years of progress’, (ed. Smith

R. A.

), 31–52; 1986, London, Pergamon.

B.-T.

and LAIRD

: Acta Metall., 1989, 37, 325–336.

HARVEY

S. E.

, MARSH

P. G.

, and GERBERICH

w. W.

: Acta Metall. Mater., 1994, 42, 3493–3502.

FLECK

N. A.

, KANG

K. J.

, and ASHBY

M. F.

: Acta Metall. Mater., 1994, 42, 365–381.

10.

PARIS

P. C.

, GOMEZ

M. P.

, and ANDERSON

W. P.

: Trend Eng., 1961, 13, 9–14.

11.

KITAGAWA

and TAKAHASHI

: in Proc. 2nd Int. Conf. ‘Mechanical behavior of materials’, 627-631; 1976, Metals Park, OH, American Society for Metals.

12.

SURESH

and RITCHIE

R. O.

: Int. Met. Rev., 1984, 29, 445–476.

13.

MILLER

K. J.

and RIOS

E. R. DE LOS

(eds.): ‘The behaviour of short fatigue cracks’: 1992, London, Mechanical Engineering Publications.

14.

RICHIE

R. O.

and LANKFORD

(eds.): ‘Small fatigue cracks’; 1986, Warrendale, PA, TMS-AIME.

15.

MILLER

K. J.

: Fatigue Fract. Eng. Mater. Struct., 1982, 5, 223–232.

16.

BOYD-LEE

and KING

J. E.

: Fatigue Fract. Eng. Mater. Struct., 1994, 17, 1–14.

17.

TANAKA

, NAKAI

, and YAMASHITA

: Int. J. Fract., 1981, 17, 519–533.

18.

LANKFORD

: Fatigue Fract. Eng. Mater. Struct., 1982, 5, 233–248.

19.

CHAN

K. S.

and LANKFORD

: Scr. Metall., 1983, 17, 529–532.

20.

X. -D.

and EDWARDS

: Eng. Fract. Mech., 1996, 54, 35–48.

21.

LAIRD

and SMITH

G. C.

: Philos. Mag., 1962, 7, 847–857.

22.

TOMKINS

and BIGGS

W. D.

: J. Mater. Sci., 1969, 4, 544–553.

23.

PELLOUX

R. M. N.

: Eng. Fract. Mech., 1970, 1, 697–704.

24.

NEUMANN

: Acta Metall., 1974, 22, 1155–1165.

25.

KUO

A. S.

and Scr

H. W.

Metall., 1976, 10, 723–728.

26.

WEERTMAN

: in ‘Fatigue and microstructure’, (ed. Meshii

), 279-306; 1979, Metals Park, OH, ASM.

27.

TOMKINS

: Fatigue Fract. Eng. Mater. Struct., 1996, 19, 1295–1300.

28.

VINOGRADOV

, HASHIMOTO

, and MIURA

: Acta Metall. Mater., 1995, 43, 675–680.

29.

ZHANG

J. Z.

, HALLIDAY

M. D.

, and BOWEN

: Mater. Sci. Technol, 1998, 14, 193–200.

30.

HALLIDAY

M. D.

and BEEVERS

C. J.

: in ‘Aluminium alloys — their physical and mechanical properties’, (ed. Arnberg

et al), Vol. 3, 526-532; 1992, Oslo, The Norwegian Institute of Technology/SINTEF Metallurgy.

31.

HALLIDAY

M. D.

, POOLE

, and BOWEN

: Fatigue Fract. Eng. Mater. Struct., 1995, 18, 717–729.

32.

HALLIDAY

M. D.

, ZHANG

J. Z.

, POOLE

, and BOWEN

: Int. J. Fatigue, 1997, 19, 273–282.

33.

PICKARD

A. C.

: ‘The application of 3-dimensional finite element methods to fracture mechanics and fatigue life prediction’: 1986, Warley, UK, EMAS.

34.

HALLIDAY

M. D.

and BOWEN

: In-situ SEM studies of small crack behaviour under cyclic load’, unpublished DERA research report, Farnborough, UK, June 1994.

35.

THOMPSON

, WADSWORTH

N. J.

, and LOUAT

: Philos. Mag., 1956, 1, 113–126.

36.

KING

J. E.

: Fatigue Fract. Eng. Mater. Struct., 1981, 4, 311–320.

37.

HALLIDAY

M. D.

and BOWEN

: In-situ SEM studies of small crack behaviour under cyclic load’, unpublished DERA research report, Farnborough, UK, September 1995.

38.

LAL

K. M.

and GARG

S. B. L.

: Eng. Fract. Mech., 1977, 9, 939–949.

39.

MAZUNDAR

P. K.

: Acta Metall., 1986, 34, 2487–2492.

40.

NAVARRO

and RIOS

E. R. DE LOS

Philos. Mag. A, 1988, 57A, 15–36.

41.

ZHANG

Y. H.

and EDWARDS

: Mater. Sci. Eng. A, 1994, A188,121–132.

42.

POOK

L. P.

: ‘The role of crack growth in metal fatigue’: 1989, London, The Metals Society.

43.

COX

B. N.

and w L. MORRIS: Eng. Fract. Mech., 1988, 31,591–610.

44.

CARLSON

R. L.

and HALLIDAY

M. D.

: in Proc. 4th Int. Conf. on ‘Low cycle fatigue and elasto-plastic behaviour of materials’, Garmisch-Partenkirchen, Germany, September 1998, 511-516; 1998, Amsterdam, Elsevier Science.

45.

HALLIDAY

M. D.

and BEEVERS

C. J.

: ‘An investigation of the influence of microstructure, texture and environment on the fatigue crack growth characteristics of a—fl titanium alloys’, unpublished MOD research report, London, January 1980.

46.

HALLIDAY

M. D.

: unpublished work, 1998.