The mechanism of crack formation in thermal fatigue tests of titanium alloys

1968 ◽  
Vol 10 (9) ◽  
pp. 708-711 ◽  
Author(s):  
N. M. Pul'tsin ◽  
V. Ya. Pavlov ◽  
V. B. Pokrovskaya
Keyword(s):  
Titanium Alloys ◽  
Thermal Fatigue ◽  
Crack Formation ◽  
Fatigue Tests

Induction of preset thermally stressed states in thermal fatigue tests: Choice of testing conditions and geometry of specimens

1997 ◽  
Vol 29 (4) ◽  
pp. 369-379
Author(s):  
G. N. Tretyachenko ◽  
B. S. Karpinos ◽  
V. G. Barilo ◽  
N. G. Solovyeva
Keyword(s):  
Thermal Fatigue ◽  
Fatigue Tests ◽  
Testing Conditions ◽  
Thermally Stressed

Thermal Fatigue Characteristics of Heat-Resisting Stainless Steel for Automotive Exhaust

2007 ◽  
Vol 539-543 ◽  
pp. 4944-4949 ◽  
Author(s):  
Tae Kwon Ha ◽  
Hwan Jin Sung
Keyword(s):  
Thermal Fatigue ◽  
Stainless Steels ◽  
Fatigue Property ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Automotive Exhaust ◽  
Load Relaxation ◽  
Temperature Ranges ◽  
Fatigue Characteristics ◽  
Efficiency And Reliability

Thermal fatigue is a complex phenomenon encountered in materials exposed to cyclically varying temperatures in the presence or absence of external load. Continually increasing working temperature and growing need for greater efficiency and reliability of automotive exhaust require immediate investigation into the thermal fatigue properties especially of high temperature stainless steels. In this study, thermal fatigue properties of 304 and 429EM stainless steels have been evaluated in the temperature ranges of 200-800oC and 200-900oC. Systematic methods for control of temperatures within the predetermined range and measurement of load applied to specimens as a function of temperature during thermal cycles have been established. Thermal fatigue tests were conducted under fully constrained condition, where both ends of specimens were completely fixed. Thermal fatigue property of STS 304 was superior to that of STS 429EM. Load relaxation behavior at the temperatures of thermal cycle was closely related with the thermal fatigue property.

Thermal-fatigue tests of restraned combustor-cooling tubes

1967 ◽  
Vol 7 (6) ◽  
pp. 256-264 ◽  
Author(s):  
L. R. Avery ◽  
G. S. Carayanis ◽  
G. L. Michky
Keyword(s):  
Thermal Fatigue ◽  
Fatigue Tests

The Processing and Fatigue Characterization of TiNi and Ti-6Al-4V Porous Materials

2011 ◽  
Vol 493-494 ◽  
pp. 930-935 ◽  
Author(s):  
Emin Erkan Aşik ◽  
Gül Ipek Nakaş ◽  
Şakir Bor
Keyword(s):  
Titanium Alloys ◽  
Endurance Limit ◽  
Fatigue Behavior ◽  
Porous Titanium ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Compression Tests ◽  
Limit Values ◽  
Porous Ti ◽  
Structural Applications

Porous titanium alloys have been extensively studied in biomedical applications due to their elastic moduli similar to that of bone compared to other implant materials. Accordingly, TiNi and Ti-6Al-4V foams have been widely characterized in terms of their various mechanical properties; however, their fatigue properties have not been well studied, even though, it has a vital importance in structural applications such as medical implants. In this study, porous titanium alloys were processed via sintering at 1200 °C for 2 hours employing Mg space holder technique. TiNi and Ti-6Al-4V alloys with a porosity of 49 and 51 vol.%, respectively, were mechanically characterized by monotonic and cyclic compression tests. The compressive strength was determined to be 148 MPa for TiNi foams whereas 172 MPa for Ti-6Al-4V foams with homogenously distributed pores having diameters in the range of 250-600 µm. Endurance limit values were determined relative to the yield strength of each porous alloy in order to enable the comparison of fatigue behavior. The fatigue tests applied with a frequency of 5 Hz and a constant stress ratio (σmin/σmax) of 0.1 have revealed that porous TiNi alloys have an endurance limit of approximately 0.6 σy whereas porous Ti-6Al-4V alloys have an endurance limit of approximately 0.75 σy. The differences and similarities in the microstructure and their effect on mechanical behavior of the two alloys were also studied by employing scanning electron microscope (SEM).

Cyclic and High Strain Behavior of Titanium Alloys Used for Riser Components

2008 ◽  
Author(s):  
C. F. G. Baxter
Keyword(s):  
Stress Relaxation ◽  
Titanium Alloys ◽  
Elevated Temperatures ◽  
Fatigue Testing ◽  
Strain Curve ◽  
Cyclic Stress ◽  
Fatigue Tests ◽  
Cyclic Behavior ◽  
Fatigue Data ◽  
Stress Ratios

Grades 23 and 29 titanium alloys are becoming more commonly used offshore for critical components of riser systems. Many of these components, such as compact flanges, operate at high mean strains due to make-up loads, often close to or above yield. Hitherto, weld fatigue data collected at low mean strains have been used for prediction of fatigue lives of such components. However, these analyses have resulted in short but adequate lives. The objective of this work was, therefore, to derive fatigue data that could be applied to components operating at high strains and over a large range of stress ratios. This necessitated strain-controlled fatigue testing. Cyclic material properties evaluated from the tests are presented. In addition, it was found that sustained strain load, a type of stress relaxation that, unlike normal stress relaxation, does not require elevated temperatures, affected the cyclic behavior It also affects the distribution of make up stresses. This phenomenon was also investigated and it was shown that the cyclic stress/strain curve, readily derived from strain-controlled fatigue tests, accounted for sustained strain load effects.

Thermal fatigue tests with actively cooled divertor mock-ups for ITER

1998 ◽  
Vol 39-40 ◽  
pp. 551-557 ◽  
Author(s):  
M. Rödig ◽  
R. Duwe ◽  
C. Ibbott ◽  
D. Jacobson ◽  
G. Le Marois ◽  
...  
Keyword(s):  
Thermal Fatigue ◽  
Fatigue Tests

scholarly journals Evaluation of Estimation Methods for Shear Fatigue Properties and Correlations with Uniaxial Fatigue Properties for Steels and Titanium Alloys

2018 ◽  
Vol 165 ◽  
pp. 16012 ◽  
Author(s):  
Shahriar Sharifimehr ◽  
Ali Fatemi
Keyword(s):  
Titanium Alloys ◽  
Inconel 718 ◽  
Fatigue Behavior ◽  
Estimation Method ◽  
Fatigue Tests ◽  
Estimation Methods ◽  
Fatigue Properties ◽  
Modified Method ◽  
Shear Fatigue ◽  
Von Mises

The goal of this study was to evaluate the accuracy of different methods in correlating uniaxial fatigue properties to shear fatigue properties, as well as finding a reliable estimation method which is able to predict the shear fatigue behavior of steels and titanium alloys from their monotonic properties. In order to do so, axial monotonic as well as axial and torsion fatigue tests were performed on two types of steel and a Ti-6Al-4V alloy. The results of these tests along with test results of 23 types of carbon steel, Inconel 718, and three types of titanium alloys commonly used in the industry were analyzed. It was found that von Mises and maximum principal strain criteria were able to effectively correlate uniaxial fatigue properties to shear fatigue properties for ductile and brittle behaving materials, respectively. Also, it was observed that for steels and Inconel 718 obtaining shear fatigue properties from uniaxial fatigue properties which are in turn calculated from Roessle-Fatemi estimation method resulted in reasonable estimations when compared to experimentally obtained uniaxial fatigue properties. Furthermore, a modification was made to the Roessle-Fatemi hardness method in order to adjust it to fatigue behavior of titanium alloys. The modified method, which was derived from uniaxial fatigue properties of titanium alloys with Brinell hardness between 240 and 353 proved to be accurate in predicting the shear fatigue behaviors.

Thermal fatigue tests of a W-Cu duplex structure for a divertor application

1989 ◽  
Vol 9 ◽  
pp. 277-282 ◽  
Author(s):  
K. Kitamura ◽  
Y. Shibutani ◽  
M. Shibui ◽  
K. Nagata ◽  
T. Araki ◽  
...  
Keyword(s):  
Thermal Fatigue ◽  
Fatigue Tests ◽  
Duplex Structure
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