CASTING DEFECTS AND THE FATIGUE BEHAVIOUR OF AN ALUMINIUM CASTING ALLOY

Fatigue and Fracture of Engineering Materials and Structures - Tập 13 Số 3 - Trang 213-227 - 1990
Malcolm J. Couper1,2, A. E. Neeson3,2, John R. Griffiths2
1Comalco Research Centre, Thomastown, Victoria, 3074, Australia
2Department of Materials Engineering, Monash University, Clayton, Victoria 3168, Australia
3Central Laboratories, Nissan Motor Manufacturing, P.O. Box 22, Clayton, Victoria 3168, Australia.

Tóm tắt

Abstract— The fatigue properties of un‐notched polished specimens of an aluminium casting alloy have been measured for various heat‐treatment conditions and at various mean stresses. The relation between fatigue life and alternating stress is insensitive to heat‐treatment and, apparently, to mean stress. It was observed that failure initiated at interdendritic shrinkage defects: evidence of classical crack initiation from persistent slip bands was also seen but such cracks, being less severe than the casting defects, never caused failure. A fracture mechanics analysis for the growth of fatigue cracks from the pores is described. It shows that the fatigue life can be quantitatively predicted from a knowledge of the size of casting defects: in particular it explains the lack of effect of heat‐treatment and the apparent absence of a mean stress effect is shown to be caused by the variation in size of maximum defect present among the specimens tested. It is shown that reducing the size of shrinkage defects will increase the life, but only up to the stage at which initiation from persistent slip bands becomes operative.

Từ khóa


Tài liệu tham khảo

10.1016/0022-0248(75)90233-X

Saunders D. S., 1975, The fracture toughness of an aluminium casting alloy, J. Aust. Inst. Metals, 20, 33

R. W.Coade(1980)The effect of second phase particles on the ductile failure of an Al‐Mg‐Si casting alloy.Ph.D. thesis Monash University Clayton Australia .

M. J.Couper(1982)Fatigue of an Al‐Mg‐Si casting alloy.Ph.D. thesis Monash University Clayton Australia .

Pook L. P., 1980, Tests to determine the fatigue strength of steel castings containing shrinkage, J. Res. Steel Castings Res. Trade Assoc., 49, 28

Östensso B., 1973, Influence of microshrinkage cavities on the endurance limit of nodular cast iron, J. Iron Steel Inst., 211, 628

10.1016/0142-1123(82)90039-1

Parker B. A., 1982, A quantitative evaluation of microstructure of a strontium‐modified Al‐Si‐Mg alloy following prolonged solution treatment, Metals Forum, 5, 48

Austen P. R., 1975, The effects of non‐standard ageing treatments on the fracture properties of Al‐Mg‐7wt%Si alloys, J. Aust. Inst. Metals, 20, 39

Heyward R. B., 1962, Designing Against Fatigue

Smith D. M., 1981, Properties of CP601—a widely used aluminium foundry alloy

Katcher M., 1974, Effects of R‐factor and crack‐closure on fatigue crack growth for aluminium and titanium alloys, ASTM STP, 559, 264

10.1016/0013-7944(70)90028-7

10.1179/msc.1977.11.8-9.274

10.1016/0013-7944(79)90004-3

10.1016/0013-7944(79)90030-4

Dowling N. E., 1977, Crack growth during low‐cycle fatigue of smooth axial specimens, ASTM STP, 637, 97

Wilhem D., 1981, An empirical approach to determining K for surface cracks, 11

Wigant C. C., 1987, Fatigue crack growth behaviour of A356‐T6 cast aluminium alloy, Fatigue 87, 1, 165

Landgraf R. W., 1969, Determination of the cyclic stress‐strain curve, J. Mater., 4, 176

10.1179/imr.1984.29.1.445

Fathulla A., 1984, Int. Spring Meeting on Crack Initiation Under Complex Loading, 182

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Thông tin xuất bản

Fatigue and Fracture of Engineering Materials and Structures

Tập 13 Số 3

213-227

Thông tin tác giả