Growth of small fatigue cracks in PH 13-8 Mo stainless steel |
| |
Authors: | A M Patel R W Neu J A Pape |
| |
Affiliation: | (1) Arthur D. Little, Inc., 02140-2390 Cambridge, MA;(2) Present address: The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 30332-0405 Atlanta, GA |
| |
Abstract: | The growth of small fatigue cracks in PH 13-8 Mo (H1050) stainless steel under constant amplitude loading at different mean
stresses (R=0.1 and −1) under generally high cycle fatigue conditions was investigated. Small cracks were allowed to initiate naturally
at the root of a single edge notch specimen and were monitored using a surface replicating technique. It was found that the
initiation and growth of surface cracks up to 100 μm encompassed 70 to 90 pct of the total fatigue life at stress amplitudes just above the fatigue limit. Cracks of length less
than 100 μm were subject to strong influences of the microstructure and exhibited stage I (shear-dominated) growth, which was manifested
in oscillatory crack growth rates. The oscillations diminished as the crack transitioned to stage II growth. The higher stress
ratio (R=0.1) resulted in a more rapid transition from stage I to stage II growth in comparison to R=−1. After transitioning to stage II, the crack growth could be well characterized by conventional long crack tools even when
the crack was still physically small. The small crack growth behavior is shown to be similar to that of a quenched and tempered
AISI 4340 steel having a comparable strength. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|