Abstract
The influence of microstructure on the strength and fracture toughness of 18 Ni (350) maraging steel was examined. Changes in microstructure were followed by X-ray and neutron diffraction and by optical and electron microscopy. These observations have been correlated with the fracture morphology established by scanning electron microscopy. Air cooling this alloy from the austenitizing temperature results in a dislocated martensite. During the initial stage of age hardening, molybdenum atoms tend to cluster (forming preprecipitates) and the cobalt assumes short range ordered positions. Subsequent aging results in Ni3Mo and σ-FeTi with overaging being associated with the formation of equilibrium reverted austenite and Fe2Mo. The fracture behavior is examined in terms of elementary dislocation precipitate interactions. It is suggested that the development of coplanar slip in the underaged conditions leads to its increased stress corrosion susceptibility and decreased fracture toughness. The optimum aged condition is then associated with cross-slip deformation. The fracture behavior of the overaged condition is a dynamic balance between a brittle matrix and the ductile (crack blunting) reverted austenite.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
S. Floreen:Met. Rev., 1968, vol. 13, p. 115.
B. R. Banerjee, J. M. Capenos, and J. J. Hauser:Advances in Electron Metallography, p. 115, ASTM Spec. Tech. Pub. No. 396, 1966, Philadelphia, Pa.
W. A. Spitzig, J. M. Chilton, and C. J. Barton:Trans. ASM, 1968, vol. 61, p. 635.
G. W. Tuffnell and R. L. Cairns:Trans. ASM, 1968, vol. 61, p. 798.
C. S. Carter:Met. Trans., 1970, vol. 1, p. 1551.
B. D. Cullity:Elements of X-Ray Diffraction, p. 391, Addison-Wesley Co., Inc., 1956, Reading, Mass.
D. T. Peters:Trans. ASM, 1968, vol. 61, p. 62.
R. D. Schoone and E. A. Fischione:Rev. Sci. Inst., 1966, vol. 37, p. 1351.
J. M. Chilton and C. J. Barton:Trans. ASM, 1967, vol. 69, p. 528.
S. Spooner, H. J. Rack, and D. Kalish:Met. Trans., 1971, vol. 2, p. 2306.
D. H. Yates and J. C. Hamaker:Metal Progr., 1962, vol. 62, p. 97.
D. J. Abson and J. A. Whiteman:J. Iron Steel Inst., 1970, vol. 208, p. 594.
D. Kalish and H. J. Rack:Met. Trans., 1971, vol. 2, p. 2665.
D. T. Peters and S. Floreen:Trans. TMS-AIME, 1969, vol. 245, p. 2021.
B. G. Reisdorf and A. J. Baker: AFML-TR-64-390, 1965.
G. Pellester:Problems in the Load-Carrying Application of High-Strength Steels, p. 173, DMIC Rept. 210, 1964.
A. J. DeArdo, Jr. and R. D. Townsend:Met. Trans., 1970, vol. 1, p. 2573.
S. Sato and P. A. Beck:Trans. TMS-AIME, 1959, vol. 215, p. 938.
H. Gleiter and E. Hornbogen:Mater. Sci. Eng., 1967, vol. 2, p. 285.
E. Hornbogen and W. Meyer:Acta Met., 1967, vol. 15, p. 584.
V. Gerold and H. Haberkorn:Phys. Status Solidi, 1966, vol. 16, p. 675.
C. A. Pampillo and H. W. Paxton: ONR Tech. Rept. Contr. Nonr. 760(14) NR 031-707, 1970.
P. Legendre:Cobalt, 1965, vol. 29, p. 171.
G. T. Hahn and A. R. Rosenfield:Application Related Phenomena in Titanium Alloys, p. 5, ASTM Spec. Tech. Pub. No. 432, 1968, Philadelphia, Pa.
B. S. Lement, K. Kreder, and H. Tushman: ASD-TDR-62-868, Part II, 1964.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Rack, H.J., Kalish, D. The strength and fracture toughness of 18 Ni (350) maraging steel. Metall Trans 2, 3011–3020 (1971). https://doi.org/10.1007/BF02814948
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02814948