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ON OPTIMIZING MICROSTRUCTURE‐RESISTANCE TO FRACTURE IN DUPLEX FERRITE‐MARTENSITE STEELS
Author(s) -
SUZUKI H.,
OUYABU S.,
KUNIO T.,
McEVILY A. J.
Publication year - 1979
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.1979.tb01338.x
Subject(s) - materials science , martensite , ferrite (magnet) , metallurgy , microstructure , ultimate tensile strength , grain size , composite material , cracking
It was found that duplex ferrite‐martensite resulted in a significant increase in the fatigue threshold level together with an increase in yield strength. However, martensite cracking tends to induce cleavage cracks in ferrite grains under static and even cyclically repeated loads. Furthermore it causes a deterioration in (i) the tensile ductility, (ii) K 1c and (iii) apparent resistance to fatigue crack propagation. This paper is concerned with finding the proper metallurgical control for providing desirable fracture properties. It was concluded that the improvement of resistance to fracture could be achieved by, (a) increasing the yield strength (hardness) of the martensite, (b) increasing and homogenizing the width of the martensite film formed between individual ferrite grains and (c) decreasing the ferrite grain size.