Dwell-fatigue crack growth mechanisms of titanium alloy Ti-6Al-4V at room-temperature

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040033
Author(s):  
Ke Wang ◽  
Xiaopeng Sun ◽  
Yongzheng Li ◽  
Pengyu Wei ◽  
Jiarui Liu ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Dwell Time ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Behavior ◽  
Dwell Fatigue ◽  
Manned Submersible ◽  
The Relationship

Ti-6Al-4V alloy is widely used for the deep-sea manned submersible. In addition to the normal cyclic loading, the manned cabin will experience a period of dwell time in each cycle during their service life. In this research, the fatigue and dwell-fatigue crack growth behavior of Ti-6Al-4V alloy under different dwell time were studied experimentally. The mechanism of dwell-fatigue crack growth was investigated. The acceleration phenomenon of the dwell-fatigue crack growth can be directly observed in the experiment. The relationship between the crack length and the dwell time was captured under different [Formula: see text] within one cycle. The results presented that there is a saturation time for the dwell-fatigue crack growth. A prediction model is proposed to predict the dwell-fatigue crack growth behavior considering the effects of dwell time.

Influence of Dwell Time on Creep-Fatigue Crack Growth Behavior of P92 Steel Weldment at High Temperature

2005 ◽  
Vol 297-300 ◽  
pp. 794-800
Author(s):  
Byeong Soo Lim ◽  
Bum Joon Kim ◽  
D. Kim ◽  
J.W. Kim ◽  
Dong Bok Lee
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Dwell Time ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Behavior ◽  
Creep Fatigue ◽  
Creep Fatigue Crack

In this study, the creep-fatigue crack growth behavior was investigated at 600°C under the maximum load with various dwell times. Test material was P92 steel (9%Cr-2%W) weldment. The creep-fatigue crack growth behavior of the HAZ(heat affected zone) and base metal was compared. The relationship between the crack growth behavior and dwell time was studied and it was characterized using ΔK and (Ct)avg parameters. The area fraction of micro-voids/cavities at the crack tip and fracture modes were examined and the relationship between crack growth rate and dwell time was investigated. The cycle dependant crack growth rate increased with the increase in dwell time. From the results of creep-fatigue test, the crack growth rate of the HAZ was found to be faster than that of base metal. As the dwell period increased, the intergranular fracture was observed along the crack growth path with the effect of creep during the dwell period.

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