Effects of microstructure on fatigue properties of structural titanium alloys

2018 ◽  
Vol 2018 (0) ◽  
pp. OS1421
Author(s):  
Satoshi EMURA ◽  
Masuo HAGIWARA ◽  
Masao HAYAKAWA ◽  
Syuji KURODA ◽  
Norie MOTOHASHI ◽  
...  
Keyword(s):  
Titanium Alloys ◽  
Fatigue Properties

scholarly journals Effect of Nitrided-Fine Particles Peening on Formation of Nitrided Layer and Fatigue Properties of Titanium Alloys

2021 ◽  
Vol 70 (12) ◽  
pp. 869-875
Author(s):  
Shoichi KIKUCHI ◽  
Keisuke FUJITA ◽  
Koichiro NAMBU ◽  
Yuki NAKAMURA
Keyword(s):  
Titanium Alloys ◽  
Fine Particles ◽  
Nitrided Layer ◽  
Fatigue Properties

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).

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.

Tensile and fatigue properties of two titanium alloys as candidate materials for fusion reactors

2000 ◽  
Vol 283-287 ◽  
pp. 602-606 ◽  
Author(s):  
P Marmy ◽  
T Leguey ◽  
I Belianov ◽  
M Victoria
Keyword(s):  
Titanium Alloys ◽  
Fatigue Properties ◽  
Fusion Reactors

scholarly journals Nonlinear dynamics and stages of damage of Ti6Al4V and Ti45Nb titanium alloys in very high cycle fatigue

2020 ◽  
pp. 145-153
Author(s):  
M. V Bannikov ◽  
V. A Oborin ◽  
D. A Bilalov ◽  
O. B Naimark
Keyword(s):  
Titanium Alloys ◽  
High Cycle Fatigue ◽  
Three Dimensional ◽  
Fatigue Properties ◽  
Experimental Program ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Number Of Cycles ◽  
Radial Shear Rolling ◽  
Very High

The paper presents an experimental methodology aimed at evaluating a very-high cycle resource for aviation titanium alloys Vt-6 (Ti6Al4V) and Ti45Nb for medical applications with different microstructures (large-crystal and submicrocrystalline ones). The submicrocrystalline (SMC) state was obtained by an intensive plastic deformation realized in two ways: the three-dimensional forging for Ti45Nb and radial-shear rolling for Ti6Al4V. The experimental program tests high-cycle and very-high-cycle loading (number of cycles 107-109) realized using the in situ determination method of the accumulation of the irreversible fatigue damage by analyzing nonlinear forms of feedback in a closed system ultrasonic fatigue setup. This makes it possible to establish the connection of the microscopic fatigue mechanisms with the model views and consider the stages of the damage development based on the nonlinear kinetics of the defect accumulation under cyclic loading in high- and gigacycle fatigue modes. We established various relations between changes in the amplitude of the second harmonic of vibrations of the free end of the samples with different internal structures, which are associated with the mechanisms of stress relaxation and damage accumulation. The grain size reduction in Ti45Nb alloy by the three-dimensional forging improved the fatigue properties by 1.3-1.5 times, whereas for VT-6 alloy, the radial-shear rolling method could not increase the fatigue properties in the very high cycle fatigue range, which may be caused by the presence of large residual internal stresses. Based on the scale parameters obtained earlier from the fracture surface morphology and the relations established in this work, the kinetic equations for the origin and growth of fatigue cracks in the gigacycle loading range will be constructed. This equation, based on the empirical power parameters related to the structure of the material, will allow us to determine the number of cycles for the origin of an internal crack and its growth to the surface.

High-Cycle Fatigue Properties of Titanium Alloys at Cryogenic Temperatures

Materials ◽  
1992 ◽  
pp. 175-182
Author(s):  
O. Umezawa ◽  
K. Nagai ◽  
T. Yuri ◽  
T. Ogata ◽  
K. Ishikawa
Keyword(s):  
Titanium Alloys ◽  
High Cycle Fatigue ◽  
Fatigue Properties ◽  
Cryogenic Temperatures ◽  
Cycle Fatigue

Residual Stress State and Fatigue Behaviour of Laser Shock Peened Titanium Alloys

2006 ◽  
Vol 524-525 ◽  
pp. 129-134 ◽  
Author(s):  
I. Altenberger ◽  
Yuji Sano ◽  
M.A. Cherif ◽  
Ivan Nikitin ◽  
Berthold Scholtes
Keyword(s):  
Residual Stress ◽  
Titanium Alloys ◽  
Cold Work ◽  
Fatigue Behaviour ◽  
Laser Shock Peening ◽  
Fatigue Properties ◽  
Stress Profile ◽  
Laser Shock ◽  
Near Surface ◽  
Shock Peening

Laser shock peening is a very effective mechanical surface treatment to enhance the fatigue behaviour of highly stressed components. In this work the effect of different laser shock peening conditions on the residual stress depth profile and fatigue behaviour without any sacrificial coating layer is investigated for two high strength titanium alloys, Ti-6Al-4V and Timetal LCB. The results show that the optimization of peening conditions is crucial to obtain excellent fatigue properties. Especially, power density, spot size and coverage severely influence the residual stress profile of laser shock peened Ti-6Al-4V and Timetal LCB specimens. For both alloys, subsurface as well as surface compressive residual stress peaks can be obtained by varying the peening conditions. In general, Timetal LCB exhibits steeper stress gradients than Ti-6Al-4V for identical peening conditions. The main parameters affecting the fatigue life are near-surface cold work and compressive residual stresses.

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