Fatigue of Titanium Alloys

Minakawa, Kuninori

doi:10.2355/tetsutohagane1955.75.7_1104

Cited by 32 publications

(7 citation statements)

References 18 publications

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“…On the other hand, heat treatment above the ␤ transus temperature results colony and prior ␤ grain have average diameters of 150 and 825 m, respectively, as shown in Table I. [14] It is reported that these crack initiation sites are on the surface or subsurface of the specimen according to the fatigue condition, and removal of the specimen surface approximately a few 10 m by chemical polishing during fatigue increases the fatigue life. [14] It is reported that these crack initiation sites are on the surface or subsurface of the specimen according to the fatigue condition, and removal of the specimen surface approximately a few 10 m by chemical polishing during fatigue increases the fatigue life.…”

Section: Resultsmentioning

confidence: 99%

An investigation of the effect of fatigue deformation on the residual mechanical properties of Ti-6Al-4V ELI

Akahori

Niinomi

Fukunaga

2000

Metall Mater Trans A

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Tensile properties, hardness, and Charpy impact toughness of Ti-6Al-4V extralow interstitial (ELI) with equiaxed ␣ and Widmanstätten ␣ structures at various stages of fatigue were investigated. Fatigue crack initiation characteristics of the same alloy were also investigated in this study. In the equiaxed ␣ structure, fatigue cracks initiated mainly at the interface between primary-␣ grains, while in the Widmanstätten ␣ structure, they initiated across ␣ plates at an angle of around 45 deg to the stress axis. Specimens with the Widmanstätten ␣ structure fractured before adequate fatigue hardening was achieved because a multitude of microcracks readily formed. Specimens with the equiaxed ␣ structure fractured after adequate fatigue hardening developed. Tensile strength, 0.2 pct proof stress, and hardness increased clearly with increasing stress cycles and fatigue steps, particulary in the low-cycle fatigue (LCF) region, while impact toughness and elongation showed a reverse trend. It is suggested, therefore, that the dislocation density multiplies more rapidly near the specimen surface during the early stages of fatigue, while during the later stages of fatigue, dislocation density increases near the center of the specimen. Also, the dislocation multiplication will continue until saturation of the entire specimen has occurred.

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Section: Resultsmentioning

confidence: 99%

An investigation of the effect of fatigue deformation on the residual mechanical properties of Ti-6Al-4V ELI

Akahori

Niinomi

Fukunaga

2000

Metall Mater Trans A

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“…Furthermore, the fatigue ratio demonstrates more clearly the resistance to fatigue failure of materials because fatigue failure is caused at very restricted weak site in the microstructure such as ¡ phase and interface between ¡ and ¢ phases as compared with the case of tensile fracture. The fatigue cracks of the (¡ + ¢)-type titanium alloys such as Ti6Al4V, Ti6Al7Nb, and Ti-17 subjected to aging treatment after solution treatment below ¢ transus temperature having primary ¡ phase were reported to initiate at slip band formed in primary ¡ phase, 8,9) micro crack formed at interface between primary ¡ and ¢ phases, 8) interface of primary ¡ phase, 10,11) or interface between primary ¡ phase and (¢ + secondary ¡ phase)-region. 911) On the other hand, in the (¡ + ¢)-type titanium alloys such as Ti6Al4V and Ti6Al7Nb subjected to aging treatment after solution treatment over ¢ transus temperature having acicular ¡ phase in the whole microstructure, the fatigue cracks were reported to initiate in unit of colony or prior ¢ grain.…”

Section: Tensile Propertiesmentioning

confidence: 99%

Quantitative and Qualitative Relationship between Microstructural Factors and Fatigue Lives under Load- and Strain-Controlled Conditions of Ti–5Al–2Sn–2Zr–4Cr–4Mo (Ti-17) Fabricated Using a 1500-ton Forging Simulator

et al. 2019

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The fatigue lives of forged Ti-17 using a 1500-ton forging simulator subjected to different solution treatments and a common aging treatment were evaluated under both load-and strain-controlled conditions: high and low cycle fatigue lives, respectively. Then, the tensile properties and microstructures were also examined. Finally, the relationships among fatigue lives and the microstructural factors and tensile properties were examined.The microstructure after solution treatment at 1203 K, which is more than the ¢ transus temperature, and aging treatment exhibits equiaxed prior ¢ grains composed of fine acicular ¡. On the other hand, the microstructures after solution treatment at temperatures of 1063, 1123, and 1143 K, which are less than the ¢ transus temperature, and aging treatment exhibit elongated prior ¢ grains composed of two different microstructural feature regions, which are acicular ¡ and fine spheroidal ¡ phase regions. The 0.2% proof stress, · 0.2 , and tensile strength, · B , increase with increasing solution treatment temperature up to 1143 K within the (¡ + ¢) region, but decrease with further increasing solution treatment temperature to 1203 K within the ¢ region. The elongation (EL) and reduction of area (RA) decrease with increasing solution treatment temperature, and it becomes nearly 0% corresponding to a solution treatment temperature of 1203 K. The high cycle fatigue limit increases with increasing solution treatment temperature up to 1143 K, corresponding to the (¡ + ¢) region. However, it decreases with further increase in the solution treatment temperature to 1203 K in the ¢ region. The fatigue ratio in high cycle fatigue life region is increasing with decreasing solution treatment temperature, namely increasing the volume fraction of the primary ¡ phase, and it relates well qualitatively with the volume fraction of the primary ¡ phase when the solution treatment temperature is less than the ¢ transus temperature. The low cycle fatigue life increases with decreasing solution treatment temperature, namely increasing the volume fraction of the primary ¡ phase. The low cycle fatigue life relates well quantitatively with the tensile true strain at breaking of the specimen and the volume fraction of the primary ¡ phase for each total strain range of low cycle fatigue testing. [

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“…47,48) It is known that the tensile strength of a material has a close relation to the fatigue strength, 65,66) on the other hand, the elongation to fracture is also correlated with it concerning the crack propagation. 50) Although the tensile strength of Ti-Ni alloy was lower than that of Ti-6Al-4V alloy, the high fatigue strength of Ti-Ni alloy seemed to be caused by the high ductility.…”

Section: Fatigue Propertiesmentioning

confidence: 99%

Fatigue Property of Super-Elastic Ti–Ni Alloy Dental Castings

et al. 2005

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Ti-Ni alloy is a promising material in the medical and dental fields due to its special mechanical properties, especially super-elasticity. Since dental prostheses are generally used under repetitive stress condition, fatigue properties of Ti-Ni alloy castings were investigated in this study. Ti-50.85Ni (mol%) alloy ingots were used for casting, which exhibited super-elasticity at 310 K in tensile test. Specimens were prepared with a centrifugal casting machine and a magnesia-based mold material. Fatigue test was performed at 310 K under repetitive loading condition with sine-waved load. The minimum stress was set at 0 MPa to evaluate the fatigue properties and change in residual strain. The maximum stress was set in the appropriate range considering the tensile property. Ultimate tensile strength and elongation to fracture of Ti-Ni alloy castings were 732 MPa and 10.6%, respectively, which were between those of CP-Ti and Ti-6Al-4V alloy castings. The fatigue limit of Ti-Ni alloy casting (206 MPa) was equivalent to or higher than that of CP-Ti or Ti-6Al-4V alloy. There was linear correlation between the fatigue ratios to ultimate tensile strength and the elongation to fracture for Ti-Ni alloy, CP-Ti and Ti-6Al-4V alloy castings, while Ti-Ni alloy showed high fatigue ratio to proof stress, which appears to relate to the twin deformation by stress-induced martensitic transformation. The stress-strain properties of TiNi alloy castings were evaluated to be stable, and it is possible to utilize the super-elasticity in cast dental prostheses.

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Fatigue of Titanium Alloys

Cited by 32 publications

References 18 publications

An investigation of the effect of fatigue deformation on the residual mechanical properties of Ti-6Al-4V ELI

An investigation of the effect of fatigue deformation on the residual mechanical properties of Ti-6Al-4V ELI

Quantitative and Qualitative Relationship between Microstructural Factors and Fatigue Lives under Load- and Strain-Controlled Conditions of Ti–5Al–2Sn–2Zr–4Cr–4Mo (Ti-17) Fabricated Using a 1500-ton Forging Simulator

Fatigue Property of Super-Elastic Ti–Ni Alloy Dental Castings

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Fatigue of Titanium Alloys

Cited by 32 publications

References 18 publications

An investigation of the effect of fatigue deformation on the residual mechanical properties of Ti-6Al-4V ELI

An investigation of the effect of fatigue deformation on the residual mechanical properties of Ti-6Al-4V ELI

Quantitative and Qualitative Relationship between Microstructural Factors and Fatigue Lives under Load- and Strain-Controlled Conditions of Ti–5Al–2Sn–2Zr–4Cr–4Mo (Ti-17) Fabricated Using a 1500-ton Forging Simulator

Fatigue Property of Super-Elastic Ti&ndash;Ni Alloy Dental Castings

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Fatigue Property of Super-Elastic Ti–Ni Alloy Dental Castings