The fracture-resistance of a range of sintered steels containing additions of copper and carbon has been measured in terms of their critical stress-intensity factor, Kc. All the fractures were apparently of the flat plane-strain type, the micro cracking being a process of microvoid coalescence rather than of cleavage. Toughness, in terms of Kc, is shown to depend on the percentage porosity, the level of the copper addition, and the carbon content. Higher toughness is achieved with copper + carbon additions than with either independently. A major feature of the results is that toughness increases with the yield stress, a trend that is contrary to the general behaviour of wrought materials.
Get full access to this article
View all access options for this article.
References
1.
BrownW. F. and SrawleyJ. E., ‘Plane-Strain Crack Toughness Testing of High-Strength Metallic Materials’, (Special Tech. Publ. No. 410), p. 46. 1966: Philadelphia, Pa, (Amer. Soo. Test. Mat.).
2.
BarnbyJ. T., ‘Fatigue’, pp. 32, 40. 1972: London (Mills and Boon).
3.
‘Methods for Plane-Strain Fracture-Toughness Testing’, BSI DD3 1971.
4.
‘Fracture Toughness Testing and Its Applications’, (Special Tech. Publ. No. 381).1965: Philadelphia, Pa.(Amer. Soc. Test. Mat.).
HeyerR. H. and McCabeD. E., ‘Review of Developments in Plane-Strain Fracture Toughness Testing’ (edited by W. F. Brown) (Special Tech. Publ. No. 463), p. 25. 1970: Philadelphia, Pa. (Amer. Soc. Test. Mat.).
8.
PelliniW. S., Nat. Research Lab. Rep. 7406, 1972.
9.
‘Conducting Drop-Weight Tear Testing to Determine to Nil Ductility Transi-tion Temperature of Ferrite Steels’, ASTM Stand. E208-69.
