Fatigue crack growth in metastable austenitic stainless steels

Conference · Wed Jun 01 04:00:00 EDT 1988

OSTI ID:6988523

Mei, Z; Chang, G; Morris, Jr, J W

The research reported here is an investigation of the influence of the mechanically induced martensitic transformation on the fatigue crack growth rate in 304-type steels. The alloys 304L and 304LN were used to test the influence of composition, the testing temperatures 298 K and 77 K were used to study the influence of test temperature, and various load ratios (R) were used to determine the influence of the load ratio. It was found that decreasing the mechanical stability of the austenite by changing composition or lowering temperature decreases the fatigue crack growth rate. The R-ratio effect is more subtle. The fatigue crack growth rate increases with increasing R-ratio, even though this change increases the martensite transformation. Transformation-induced crack closure can explain the results in the threshold regime, but cannot explain the R-ratio effect at higher cyclic stress intensities. 26 refs., 6 figs.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6988523
• Report Number(s): LBL-24949; CONF-880653-2; ON: DE88013709
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
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ALLOYS
AUSTENITIC STEELS
CHEMICAL COMPOSITION
CRACK PROPAGATION
CRACKS
FATIGUE
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS
MATERIALS TESTING
MECHANICAL PROPERTIES
STEELS
TESTING
THERMONUCLEAR REACTOR MATERIALS