Microstructural examination of |
| |
Authors: | C Fukuoka H Yoshizawa Y G Nakagawa M E Lapides |
| |
Affiliation: | (1) Research Laboratories, Ishikawajima-Harima Heavy Industries Company, Ltd., Tokyo, Japan;(2) Electric Power Research Institute, 94304 Palo Alto, CA |
| |
Abstract: | Fatigue tests were performed to examine how microstructural conditioning influences crack initiation and propagation in SA508
class 3 low-carbon steel. A 3-mm-long crack was introduced in compact tension (CT) fatigue test specimens under four different
loads in order to obtain crack tip plastic zones at different stress intensity factor ranges, ΔK = 18, 36, 54, and 72 MPa√m.
The microstructure of the plastic zones around the crack tip were examined by trans- mission electron microscopy (TEM) and
selected area electron diffraction (SAD). Micro- orientation of the dislocation cells in the plastic zones of all of the CT
samples increased to 4 deg from the level of an as-received sample. Four-point bending fatigue tests were performed for plate
shape samples with a large cyclic strain range. The SAD value of the bending samples was also 4 deg in the damaged area where
cracks already initiated at an early stage of the fatigue process. These test results indicate that the microstructural conditioning
is a prerequisite for the fatigue crack initiation and propagation in SA508. These observations may lead to better under-
standing of how fatigue initiation processes transit to cracks. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|