Digitale Medien
Oxford, UK
:
Blackwell Publishing Ltd
Fatigue & fracture of engineering materials & structures
2 (1979), S. 0
ISSN:
1460-2695
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Maschinenbau
Notizen:
Abstract This investigation into the fatigue of a commercial austenitic stainless steel (UHB 3 MM) at ultrasonic frequencies (20 and 25 kHz) has been primarily concerned with the initial stages of the fatigue process prior to fatigue crack initiation. Results have been obtained using equipment in which it is possible to superimpose ultrasonic push pull stresses upon a static tensile stress. Microstructural examination of the specimen surface and of the internal deformation rearrangements by means of electron microscopy, has revealed fatigue damage which is comparable to that occurring during conventional, low frequency, fatigue. Thus, in contrast to other investigators, we have obtained evidence of dislocation dipole and deformation band formation together with regularly spaced slip band markings from tests at low amplitudes. Higher amplitude cycling has indicated the formation of dislocation tangles and cells.The results do not suggest a significant change in fatigue mechanism upon changing the testing frequency into the ultrasonic regime.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1111/j.1460-2695.1979.tb01346.x
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