Fatigue Crack Growth of Ti-15V-3Cr-3Sn-3Al Alloy

2012 ◽  
Vol 468-471 ◽  
pp. 1758-1761 ◽  
Author(s):  
S. T. Chang ◽  
W. J. Li ◽  
L.W. Tsay
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Fracture ◽  
Stress Ratio ◽  
High Stress ◽  
Aged Specimen ◽  
Fracture Appearance ◽  
Temperature Ranges ◽  
Crack Growth Rates

In this study, the fatigue crack growth rates (FCGRs) of Ti-15V-3Cr-3Al-3Sn alloy aged in the temperature ranges from 426 to 593 oC for 8 hrs was determined at stress ration of 0.1 or 0.5. The results of fatigue crack growth tests revealed the FCGRs decreased with increasing aging temperature. Generally, the 426oC aged specimen had the highest FCGRs among the specimens being tested, regardless of stress ratio. It was noted obvious increase in FCGRs occurred for the 482oC aged specimen at stress ratio of 0.5. Fatigue fracture appearance of various specimens tested in air exhibited predominantly transgranular fatigue fracture with coarse stripes for the specimens aged at/above 538oC. Intergranular fracture was more likely to be found in the 426oC aged specimen, and for the A482 specimen tested at high stress ratio.

Effect of Stress Ratio on Fatigue Crack Growth in 95Pb-5Sn Solder

1999 ◽  
Vol 123 (3) ◽  
pp. 311-315 ◽  
Author(s):  
J. Zhao and ◽  
Y. Mutoh ◽  
T. Ogawa
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Closure ◽  
Stress Ratio ◽  
High Stress ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Threshold Region ◽  
Test Conditions

The stress ratio effect on the fatigue crack growth behavior of 95Pb-5Sn solder has been investigated. It is found that both ΔJ and ΔK can correlate fatigue crack growth data well, which means that the crack growth behavior of the 95Pb-5Sn solder under the frequency of 10 Hz was dominantly cyclic dependent. The da/dN-ΔJ relationship can be expressed as: da/dN=1.1×10−11s˙ΔJ1.45. Low level of crack closure was found only in the near-threshold region. Except in this region, no crack closure was observed in the present test conditions. Both transgranular and intergranular fractures were observed on fracture surfaces: the former was dominant in most test conditions and the latter was dominant at the high stress ratio of 0.7. Striations and striation-like features were also found. Many slip bands and cavities along the grain boundary were observed on the crack wake and ahead of the crack tip in the high crack growth rate region.

scholarly journals Fatigue crack growth rates of 10CrNi3MoV steel welded joints considering the stress ratio

2021 ◽  
Vol 33 ◽  
pp. 802-808
Author(s):  
Wei Song ◽  
Jingjing Li ◽  
Xuesong Liu ◽  
Ping Wang ◽  
Di Wan ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Welded Joints ◽  
Stress Ratio ◽  
Crack Growth Rates

Fatigue Crack Growth of Stainless Steel Piping in a Pressurized Water Reactor Environment

1979 ◽  
Vol 101 (1) ◽  
pp. 73-79 ◽  
Author(s):  
W. H. Bamford
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Fatigue Crack Growth ◽  
Intensity Factor ◽  
Crack Growth ◽  
Growth Rates ◽  
Stress Ratio ◽  
Pressurized Water ◽  
Crack Growth Rates

Fatigue crack-growth behavior was investigated for types 304 and 316 stainless steel exposed to a pressurized water reactor environment. The effects of test frequency, stress ratio, specimen orientation, heat to heat variables and weld versus base metal performance were evaluated. Crack-growth rates were correlated with the range of crack-tip stress intensity factor, as well as the “effective stress intensity factor” proposed by Walker to account for R ratio effects. Results of the study showed that fatigue crack-growth rates in the water environment were not significantly different from results at the same stress ratio in an air environment at the same temperature. The most important parameter found to affect the crack-growth rate was the stress ratio R, and increasing values of R produced increased crack-growth rates at any given value of stress intensity factor range ΔK. The stress ratio effects were successfully accounted for by employment of the Walker model.

Definition of Fatigue Crack Growth Thresholds for Ferritic Steels in Fitness-for-Service Codes

2018 ◽  
Author(s):  
Kunio Hasegawa ◽  
Bohumir Strnadel
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Stress Ratio ◽  
Fatigue Tests ◽  
Ferritic Steels ◽  
Stress Ratios ◽  
Definition Of ◽  
Crack Growth Rates

Fatigue crack growth rates are expressed as a function of the stress intensity factor ranges. The fatigue crack growth thresholds are important characteristics of fatigue crack growth assessment for the integrity of structural components. Almost all materials used in these fatigue tests are ferritic steels. As a result, the reference fatigue crack growth rates and the fatigue crack growth thresholds for ferritic steels were established as rules and they were provided by many fitness-for-service (FFS) codes. However, the thresholds are not well defined in the range of negative stress ratio. There are two types of thresholds under the negative stress ratio. That is, constant thresholds and increment of thresholds with decreasing stress ratios. The objective of this paper is to introduce the thresholds provided by FFS codes and to analyze the thresholds using crack closure. In addition, based on the experimental data, definition of the threshold is discussed to apply to FFS codes. Finally, threshold for ferritic steels under the entirely condition of stress ratio is proposed to the ASME Code Section XI.

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