Fractographic investigations of the easing of crack propagation in hardened steels by water

Autor: O. N. Romaniv, Yu. V. Zima, G. N. Nikiforchin, N. L. Kuklyak
Rok vydání: 1976
Předmět:
Zdroj: Soviet Materials Science. 11:143-148
ISSN: 1573-885X
0038-5565
DOI: 10.1007/bf00716896
Popis: The fractographic observations described here show convincingly that a weakening of the resistance to crack propagation due to the effect of water is associated with an increase of fracture brittleness in the microvolumes, which is observed with structural steels of different structures when various failure mechanisms are operative. If the IC mechanisms operate in crack propagation, then water has an increasing effect on ZECP, accompanied by a reduction in microplastic strain during failure along grain boundaries. If some other mechanisms are operative in crack propagation then the barrier band of increased resistance to fracture becomes narrower. In most cases the drawing zone and the pit zone, located near the starting areas of the fracture, act as this band. The coalescence of microcavities accompanied by the formation of low energy pits, becomes replaced here by a quasifracture mechanism which, in turn, becomes a transcrystalline cleavage. In high-tempered 50Kh steel the barrier pit zone is often replaced by direct intercrystalline cleavage.
Databáze: OpenAIRE
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