Cast, wrought, and directly sintered smooth and precracked beam specimens of BT1 steels were studied in three- and four-point bending at room temperature. Following austenitization at 1250° C and tempering between 500 and 560° C, brittle fracture strengths varied between 1.1 and 2.8 GN m−2 and the fracture toughness of the materials was in the range 18 to 25 MN m−3/2. Combining these data, the critical Griffith-Irwin flaw sizes were calculated to be typically of the order of 100 μm. This is in reasonable agreement with the observed sizes of some failure-initiating sites, particularly pores in sintered material, but generally several times larger than the carbide and grain sizes. In wrought specimens, failure frequently originated from groups of carbides, apparently fracturing on contiguous planes. No evidence of sub-critical cracking of carbides was detected (as in BT42), in contrast to BM2, BT6 and sintered and hot isostatically pressed BT1. Only inter-powder particle parting occurred in this sintered material. Conventional fracture mechanics thus successfully interprets results on sintered specimens, but only on several of the wrought specimens. For the majority of the latter it appears necessary to invoke operation of propagation mechanisms involving “short”, ≈10 μm, cracks under monotonic loading or to associate the brittle fracture stress with that for crack nucleation: e.g. cleavage of a carbide cluster.
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W. J. C. Price, M. M. Rebbeck, A. S. Wronski andS. A. Amen,Powder Metall. 28 (1985) 1.
W. J. C. Price, M. M. Rebbeck andA. S. Wronski,28 (1985) 9.
S. A. Amen, PhD Thesis, University of Bradford (1985).
J. A. Rescalvo andB. L. Averbach,Met. Trans. A 10 (1979) 1265.
K. Eriksson,Scand. J. Metall. 4 (1975) 182.
A. S. Wronski, L. B. Hussain Al-Yasiri andF. L. Jagger,Powder Metall. 22 (1979) 109.
P. W. Shelton andA. S. Wronski,Metal Sci. 17 (1983) 533.
C. S. Wright, A. S. Wronski andM. M. Rebbeck,Metals Technol. 11 (1984) 181.
P. W. Shelton andA. S. Wronski,Mater. Sci. Technol. 3 (1987) 260.
K. Kiyonaga, in “Towards Improved Ductility and Toughness”, Koyoto International Conference, October 1971 (Iron and Steel Institute of Japan) p. 207.
L. R. Olsson andH. F. Fischmeister,Powder Metall. 21 (1978) 13.
D. A. Curry andJ. F. Knott,Met. Sci. 13 (1979) 341.
M. Jeandin, C. Aubin andY. Bienvenu,Metal Powder Rep. 37 (1982) 187.
R. W. Rice, “Fractography of Ceramic and Metal Failures”, ASTM STP 827, edited by J. J. Mecholsky Jr and S. R. Powell Jr (American Society for Testing and Materials, Philadelphia, Pennsylvania, 1984) p. 5.
E. A. Almond, B. Roebuck andM. G. Gee,Met. Mater. 2 (1986) 76.
M. E. Fine andR. D. Ritchie, “Fatigue and Microstructure” (American Society for Metals, Metals Park, Ohio, 1979) p. 345.
T. Okada andG. Sines,J. Amer. Ceram. Soc. 66 (1983) 719.
T. Hoshide, H. Furuya, Y. Nagase andT. Yamada,Int. J. Fract. 26 (1984) 229.
L. R. F. Rose,J. Mater. Sci. Lett. 5 (1986) 455.
L. Fontaine andA. S. Wronski, unpublished results (1986).
C. S. Wright andL. Fontaine, Colloque “Nouvelles Poudres, Nouveaux Produits en Metallurgie des Poudres et Céramiques Spéciales” (Groupe Français de la Céramique and Société Française de Metallurgie, Paris, 1988) pp. 22–1.
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Wronski, A.S., Rebbeck, M.M. & Amen, S.A. Fracture mechanisms and mechanics of an 18-4-1 high speed steel. J Mater Sci 23, 2213–2219 (1988). https://doi.org/10.1007/BF01115790
- Fracture Toughness
- Fracture Stress
- Brittle Fracture
- Fracture Strength