Corrosion of metals and alloys. Measurement of environmentally assisted small crack growth rate

2018 ◽  
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Metals And Alloys ◽  
Small Crack ◽  
Small Crack Growth

scholarly journals Fatigue. Unified Description of Small Crack Growth Rate Using .DELTA.CTOD in Both HCF and LCF Conditions.

1997 ◽  
Vol 46 (10) ◽  
pp. 1173-1177
Author(s):  
Masahiro MIYAKE ◽  
Shoji HARADA ◽  
Yosihito KUROSIMA ◽  
Masao TAKAHARA
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Small Crack ◽  
Small Crack Growth ◽  
Unified Description

scholarly journals Relation Between Scatter in Crack Growth Rate and Small Crack Growth Law.

1994 ◽  
Vol 43 (494) ◽  
pp. 1469-1474
Author(s):  
Masahiro GOTO ◽  
Norio KAWAGOISHI ◽  
Hironobu NISITANI ◽  
Hiroomi MIYAGAWA ◽  
Yasuji ODA
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Small Crack ◽  
Small Crack Growth

Surface Small Crack Growth Behavior of Type 304 Stainless Steel in Low-Cycle Fatigue at Elevated Temperature

1988 ◽  
Vol 110 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Masakazu Okazaki ◽  
Tomohiro Endoh ◽  
Takashi Koizumi
Keyword(s):  
Growth Rate ◽  
Grain Size ◽  
Crack Growth Rate ◽  
Grain Boundaries ◽  
Crack Growth ◽  
Low Cycle Fatigue ◽  
Small Crack ◽  
Average Grain Size ◽  
Small Crack Growth ◽  
Macroscopic Crack

Surface small crack growth behavior of Type 304 stainless steel during low cycle fatigue under fast-fast and slow-fast cyclings was investigated at a temperature of 873 K by using the smooth specimens which had the different grain sizes. It was shown that the crack, which had already grown up to a few grain size, predominantly propagated with strain cycling, and that it was very important for the safety assessment of the components in service to detect the crack of a few grain sizes. It was also shown that small crack growth rate showed the minimum when they arrived at the grain boundaries. Above behavior resulted from that the grain boundaries temporarily impeded the small crack growth. The crack length below which the grain boundaries notably affected the small crack growth rate was also given as the function of relative length to the average grain size. Furthermore, the small crack growth rate was compared with the macroscopic crack growth one. In fast-fast cycling, the small crack growth rate was about ten times as large as the macroscopic crack growth one, where its length was comparable to the grain size. Based on the results thus obtained, the application limit of macroscopic crack growth law to the surface small crack growth was discussed. The application limit proportionally increased with the grain size, and it was about ten times average grain size in both fast-fast and slow-fast cyclings.

SMALL CRACK GROWTH BEHAVIOR AND EVALUATION OF GROWTH RATE OF COPPER PROCESSED BY EQUAL CHANNEL ANGULAR PRESSING

2012 ◽  
Vol 06 ◽  
pp. 245-250
Author(s):  
KUSNO KAMIL ◽  
MASAHIRO GOTO ◽  
SEUNG-ZEON HAN ◽  
KWANGJUN EUH ◽  
NORIO KAWAGOISHI ◽  
...  
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Plastic Zone Size ◽  
Growth Behavior ◽  
Small Crack ◽  
Stress Intensity Factor Range ◽  
Crack Growth Behavior ◽  
Angular Pressing ◽  
Average Grain Size

Ultrafine grained copper processed by 4 cycles of equal angular pressing was fatigued to study the growth behavior of a small crack. After the crack initiation, the behavior of a major crack was monitored through plastic replication technique, showing that the crack growth rate is proportional to the crack length regardless of stress amplitudes. The crack growth rate of major cracks was evaluated by a term σanl, not by the stress intensity factor range, ΔK. Analysis on fracture surfaces by scanning electron microscopy showed a planar followed by a striated surface. The formation mechanism of fracture surface morphologies was discussed by considering the average grain size and the reversible plastic zone size at a crack tip.

scholarly journals Fatigue and Crack Growth under Constant- and Variable-Amplitude Loading in 9310 Steel Using “Rainflow-on-the-Fly” Methodology

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 807
Author(s):  
James C. Newman
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Crack Nucleation ◽  
Flaw Size ◽  
Constant Amplitude ◽  
Large Crack ◽  
Small Crack Growth ◽  
Spectrum Loading

Fatigue of materials, like alloys, is basically fatigue-crack growth in small cracks nucleating and growing from micro-structural features, such as inclusions and voids, or at micro-machining marks, and large cracks growing to failure. Thus, the traditional fatigue-crack nucleation stage (Ni) is basically the growth in microcracks (initial flaw sizes of 1 to 30 μm growing to about 250 μm) in metal alloys. Fatigue and crack-growth tests were conducted on a 9310 steel under laboratory air and room temperature conditions. Large-crack-growth-rate data were obtained from compact, C(T), specimens over a wide range in rates from threshold to fracture for load ratios (R) of 0.1 to 0.95. New test procedures based on compression pre-cracking were used in the near-threshold regime because the current ASTM test method (load shedding) has been shown to cause load-history effects with elevated thresholds and slower rates than steady-state behavior under constant-amplitude loading. High load-ratio (R) data were used to approximate small-crack-growth-rate behavior. A crack-closure model, FASTRAN, was used to develop the baseline crack-growth-rate curve. Fatigue tests were conducted on single-edge-notch-bend, SEN(B), specimens under both constant-amplitude and a Cold-Turbistan+ spectrum loading. Under spectrum loading, the model used a “Rainflow-on-the-Fly” subroutine to account for crack-growth damage. Test results were compared to fatigue-life calculations made under constant-amplitude loading to establish the initial microstructural flaw size and predictions made under spectrum loading from the FASTRAN code using the same micro-structural, semi-circular, surface-flaw size (6-μm). Thus, the model is a unified fatigue approach, from crack nucleation (small-crack growth) and large-crack growth to failure using fracture mechanics principles. The model was validated for both fatigue and crack-growth predictions. In general, predictions agreed well with the test data.

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