Fatigue of in situ Reinforced Ti–8.5Al–1B–1Si

1997 ◽  
Vol 12 (4) ◽  
pp. 1102-1111 ◽  
Author(s):  
S. Rangarajan ◽  
P. B. Aswath ◽  
W. O. Soboyejo
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Low Cycle Fatigue ◽  
Effect Of Temperature ◽  
Crack Growth Rates ◽  
Better Than

The effect of temperature on the fatigue and fracture properties of an in situ reinforced super α alloy Ti–8.5Al–1B–1Si (wt. %) was investigated. At room temperature the as-extruded composite has a strength of 631 MPa with limited ductility. On increasing the temperature to 700 °C only a marginal drop in strength to 610 Mpa was observed along with a significant improvement in ductility to 5.9%. Low-cycle fatigue results indicate a marginal decrease in fatigue life as temperature is increased from room temperature to 700 °C. Fatigue crack growth studies in the as-extruded microstructure indicate a strong influence of R-ratio on both the threshold for fatigue crack growth and crack growth rates in the Paris regimes. At elevated temperatures, the resistance to fatigue crack growth increases with temperature below approximately 500 °C. At 600 °C, however, there is an increase in the near threshold crack growth rate due to embrittlement effects. At higher δK values , the resistance to fatigue crack growth at elevated temperatures is always better than that at room temperature. This improvement is attributed to the increase in the inherent resistance

Fatigue Crack Growth Properties of 16MnR and 316L Steels at High Temperature

2005 ◽  
Author(s):  
Zengliang Gao ◽  
Weiming Sun ◽  
Weiya Jin ◽  
Ying Wang ◽  
Fang Zhang
Keyword(s):  
Fatigue Crack ◽  
High Temperature ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Fatigue Cracks ◽  
Pressure Vessels ◽  
Effect Of Temperature ◽  
Growth Properties ◽  
Crack Growth Rates

Fatigue failures often take place in high temperature pressure vessels and equipment because of fluctuation of pressure and temperature. Fatigue crack growth properties of materials at high temperatures are very important for safety assessment of high temperature equipment. A series of fatigue crack growth tests were carried out, and fatigue crack growth rates were determined at 25∼500°C for typical steels 316L and 16MnR. The laws of fatigue crack growth of two materials at different temperatures and the effect of temperature on fatigue crack growth rates were studied. The results show that the crack growth rates increase with temperature for 316L steel. Both the exponent n and constant C for Paris law change with temperature. The fatigue cracks of 16MnR propagate at 150 °C and 300 °C more slowly than at room temperature and 425 °C. The fatigue crack growth rate at 425 °C is the highest for temperature range of 25–425 °C.

scholarly journals Fatigue-Crack Growth-Rate Studies of Low-Alloy Pressure-Vessel Steels

1968 ◽  
Vol 90 (4) ◽  
pp. 648-655 ◽  
Author(s):  
D. F. Mowbray ◽  
W. R. Andrews ◽  
A. J. Brothers
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Crack Extension ◽  
Room Temperature ◽  
Plate Thickness ◽  
Pressure Vessel Steels ◽  
Class B ◽  
Crack Growth Rates

Fatigue-crack growth rates were determined at room temperature for ASTM A302-Class B and A 508-Class 2 steels in two characteristic plate and forging directions. Tests were performed under zero-to-tension cyclic loading using both through-crack and part-through-crack plate specimens. Crack growth rates in the through-crack specimens, though affected by plate or forging directions, were found to correlate well upon the hypothesis that the crack extension per cycle is proportional to a positive power of the range of alternating stress intensity factor. In addition, the rate of crack extension through the plate thickness of the surface-crack specimens was successfully correlated with data from through-crack specimens.

Experimental Research on Crack Propagation in U71Mn and U75V Rail Steels

2006 ◽  
Vol 324-325 ◽  
pp. 807-810
Author(s):  
Jing Jing Li ◽  
Ya Fang Guo ◽  
Yue Sheng Wang ◽  
Chang Hai Tian
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Rail Steel ◽  
Mode I ◽  
Static Loads ◽  
In Situ Observations ◽  
Electronic Microscope ◽  
Better Than

In this paper, the continuous in-situ observations of the fatigue crack growth in U71Mn and U75V rail steel are made by using the scanning electronic microscope (SEM). The microstructure patterns of cracks under the mode I fatigue loads and quasi-static loads are presented. The results indicate that the short fatigue crack growth in rail steel is a quasi-cleavage fracture. The ductility and the performance of fatigue resistance of U71Mn rail steel are better than those of U75V rail steel.

Effects of Tension-Compression Cycling on Fatigue Crack Growth in High Strength Alloys

1971 ◽  
Vol 93 (4) ◽  
pp. 893-896 ◽  
Author(s):  
T. W. Crooker
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Low Cycle Fatigue ◽  
Plate Thickness ◽  
High Strength ◽  
Simple Zero ◽  
Pressure Vessels ◽  
Crack Growth Rates

Crack growth by low-cycle fatigue is a potential failure mechanism for welded pressure vessels. Residual stresses remaining from fabrication or caused by localized plastic deformation incurred in shakedown can result in operating stress cycles approaching fully-reversed tension-compression. However, virtually all of the fatigue crack propagation data reported in the literature for structural alloys are generated under simple, zero-tension cycling, and their direct application to such problems is questionable. This paper presents the results of a study which shows that the compression portion of fully-reversed tension-compression cycling can contribute substantially to fatigue crack growth rates in plate thickness medium-to-high strength alloys. Data from several alloys show a 50 percent increase in fatigue crack growth rates due to tension-compression cycling. The implications of these findings and methods for applying the results of this study are discussed.

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