Stress-based fatigue behavior of Ti–6Al–4V alloy with a discontinuous lamellar microstructure fabricated by thermomechanical powder consolidation

2020 ◽  
Vol 798 ◽  
pp. 140085 ◽  
Author(s):  
Lei Meng ◽  
Jingbo Gao ◽  
Jukun Yue ◽  
Jingfan Zhang ◽  
Xiaoli Zhao ◽  
...  
Keyword(s):  
Fatigue Behavior ◽  
Lamellar Microstructure ◽  
Powder Consolidation

Fracture and Fatigue Behavior in Nb3Al+ Nb Intermetallic Composites

1992 ◽  
Vol 273 ◽  
Author(s):  
L. Murugesh ◽  
K. T. Venkateswara ◽  
L. C. DeJonghe ◽  
R. O. Ritchie
Keyword(s):  
Fatigue Behavior ◽  
Strong Dependence ◽  
Lamellar Microstructure ◽  
Intensity Level ◽  
Reaction Sintering ◽  
High Melting Point ◽  
Intermetallic Matrix ◽  
Strain Fracture ◽  
Fatigue And Fracture

ABSTRACTModel high-melting point Nb3Al + Nb intermetallic composites have been fabricated in situ by vacuum hot pressing and reaction sintering elemental powders mixed in the ratio Nb + 7wt. % Al. In both cases, microstructures feature islands of ductile Nb solid solution (∼20 vol. %) in a brittle Nb3Al intermetallic matrix. Thermal treatment for 24 h at 1800°C results in a lamellar microstructure containing a uniform and fine distribution of filamentary Nb in a Nb3Al matrix following the massive peritectic transformation. In this paper, the fatigue and fracture resistance of these two microstructures are examined and compared to pure Nb3Al and Nb. Preliminary results suggest that the Nb phase can provide significant toughening to Nb3Al via crack bridging, plastic stretching and interfacial debonding mechanisms. Measured plane-strain fracture toughness values for the as hot-pressed and fully-aged microstructures are ∼6–8 Mpa√m compared to √fm for pure Nb3Al. However, under cyclic loading, the composites tend to show a strong dependence on applied stress-intensity level; fatigue thresholds range between 2–3 Mpa√m.

Evaluation of the Fretting Fatigue Behavior of Ti-6Al-4V Alloy

2005 ◽  
Vol 297-300 ◽  
pp. 1089-1094
Author(s):  
Jae Do Kwon ◽  
Yong Tak Bae ◽  
Sung Jong Choi ◽  
Young Suck Chai ◽  
Hitoshi Ishii
Keyword(s):  
Titanium Alloy ◽  
Fatigue Limit ◽  
Degradation Mechanism ◽  
Fatigue Behavior ◽  
Lamellar Microstructure ◽  
Fretting Fatigue ◽  
Mechanical Tests ◽  
Structural Components ◽  
Specific Strength ◽  
Fretting Damage

Fretting is a potential degradation mechanism of structural components and equipments exposed to various environments and loading conditions. It is well known that the fatigue life under fretting condition decreases approximately 50-70% compared with that under non-fretting fatigue condition. The specific gravity of titanium alloy is 4.5 which is lighter than steel, however, its specific strength, heat and corrosion resistance are superior to steel. Ti-6Al-4V alloy is a kind of a+b phase titanium alloy, and mechanical properties are changed by alloy elements, shapes and distributions of microstructures. In this study, three different kinds of specimens are prepared under different heat treatments in order to produce different microstructures. Through various kinds of mechanical tests, the following conclusions are observed: 1) The microstructures are observed as equiaxed, bimodal and lamellar microstructures respectively. 2) The elongation percentage is superior for the equiaxed microstructure, and the hardness and tensile strength are superior for the lamellar microstructure. 3) The plain fatigue limit of lamellar structure shows higher value than that of the equiaxed and bimodal structures. 4) The fretting fatigue limit considerably decreases compared with the plain fatigue limit for all materials. 5) The fretting damage of contact surface increases with an increase of cyclic loading amplitude under the constant contact pressure.

High cycle fatigue behavior of Ti–5Al–5Mo–5V–3Cr–1Zr titanium alloy with lamellar microstructure

2017 ◽  
Vol 682 ◽  
pp. 107-116 ◽  
Author(s):  
Chaowen Huang ◽  
Yongqing Zhao ◽  
Shewei Xin ◽  
Changsheng Tan ◽  
Wei Zhou ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Lamellar Microstructure ◽  
Cycle Fatigue

scholarly journals Effect of Plasma Nitriding on Fatigue Behavior of Ti-6Al-4V Alloy

2018 ◽  
Author(s):  
Michele C. B. de Castro ◽  
Antônio A. Couto ◽  
Gisele F. C. Almeida ◽  
Marcos Massi ◽  
Nelson B. de Lima ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Diffraction Analysis ◽  
Low Cycle Fatigue ◽  
Plasma Nitriding ◽  
Fatigue Behavior ◽  
Lamellar Microstructure ◽  
Titanium Nitrides ◽  
X Ray Diffraction ◽  
Average Roughness ◽  
X Ray

The Ti-6Al-4V alloy is widely used in the manufacture of components that should have low density, high corrosion resistance, and fatigue strength. The fatigue strength can be improved by surface modification. The aim of this study was to determine the influence of plasma nitriding on the fatigue behavior of Ti-6Al-4V alloy with a lamellar microstructure (Widmanstätten type). Nitriding was executed at 720 °C for 4 hours in an atmosphere with N2, Ar and H2. Samples microstructure characterization was carried out by X-ray diffraction analysis, optical microscopy and scanning electron microscopy. The average roughness of the specimens was determined, and fatigue tests were executed in a bending-rotating machine with reverse tension cycles (R= -1). X-ray diffraction analysis revealed the matrix phases α and β, and the phases Ɛ-Ti2N and δ-TiN in the nitrided alloy. A nitrogen diffusion layer was formed between the substrate and the titanium nitrides. Plasma nitriding resulted in an increase in low cycle fatigue strength, whereas at high cycles, both conditions exhibit similar behavior. The fracture surface of the fatigue tested specimens clearly revealed the lamellar microstructure. The fracture mechanism appears to be due to cracking at the interface of α and β phases of the lamellar microstructure.

scholarly journals The Effect of Plasma Nitriding on the Fatigue Behavior of the Ti-6Al-4V Alloy

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 520 ◽  
Author(s):  
Michele de Castro ◽  
Antônio Couto ◽  
Gisele Almeida ◽  
Marcos Massi ◽  
Nelson de Lima ◽  
...  
Keyword(s):  
Fatigue Strength ◽  
Diffraction Analysis ◽  
Low Cycle Fatigue ◽  
Plasma Nitriding ◽  
Fatigue Behavior ◽  
Lamellar Microstructure ◽  
Titanium Nitrides ◽  
X Ray Diffraction ◽  
Average Roughness ◽  
X Ray

The Ti-6Al-4V alloy is widely used in the manufacture of components that must have low density and high corrosion resistance and fatigue strength. The fatigue strength can be improved by surface modification. The aim of this study was to determine the influence of plasma nitriding on the fatigue behavior of a Ti-6Al-4V alloy with a lamellar microstructure (Widmanstätten type). Nitriding was executed at 720 °C for 4 h in an atmosphere with N2, Ar, and H2. Microstructure characterization of the samples was carried out by X-ray diffraction analysis, optical microscopy, and scanning electron microscopy. The average roughness of the specimens was determined, and fatigue tests were executed in a bending–rotating machine with reverse tension cycles (R = −1). X-ray diffraction analysis of the nitrided alloy revealed the following matrix phases: α, β, ε-Ti2N, and δ-TiN. A nitrogen diffusion layer was formed between the substrate and the titanium nitrides. Plasma nitriding resulted in an increase in low-cycle fatigue strength, whereas at high cycles of 200 MPa, both conditions exhibited similar behaviors. The fracture surface of the fatigue-tested specimens clearly revealed the lamellar microstructure. The fracture mechanism in the non-nitrided specimens appears to be due to cracking at the interface of the α and β phases of the lamellar microstructure.

THE FATIGUE BEHAVIOR OF FRESHWATER ICE

1987 ◽  
Vol 48 (C1) ◽  
pp. C1-329-C1-335 ◽  
Author(s):  
W. A. NIXON ◽  
R. A. SMITH
Keyword(s):  
Fatigue Behavior ◽  
Freshwater Ice

Calculating Energy Release Rate as a Function of Crack Length Using a Multiple-Step Crack Closure Technique in Tire Finite Element Models

2018 ◽  
Vol 46 (3) ◽  
pp. 130-152
Author(s):  
Dennis S. Kelliher
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Crack Length ◽  
Energy Release ◽  
Crack Closure ◽  
Release Rate ◽  
Fatigue Behavior ◽  
Three Dimensions ◽  
Quantitative Prediction ◽  
Closure Technique

ABSTRACT When performing predictive durability analyses on tires using finite element methods, it is generally recognized that energy release rate (ERR) is the best measure by which to characterize the fatigue behavior of rubber. By addressing actual cracks in a simulation geometry, ERR provides a more appropriate durability criterion than the strain energy density (SED) of geometries without cracks. If determined as a function of crack length and loading history, and augmented with material crack growth properties, ERR allows for a quantitative prediction of fatigue life. Complications arise, however, from extra steps required to implement the calculation of ERR within the analysis process. This article presents an overview and some details of a method to perform such analyses. The method involves a preprocessing step that automates the creation of a ribbon crack within an axisymmetric-geometry finite element model at a predetermined location. After inflating and expanding to three dimensions to fully load the tire against a surface, full ribbon sections of the crack are then incrementally closed through multiple solution steps, finally achieving complete closure. A postprocessing step is developed to determine ERR as a function of crack length from this enforced crack closure technique. This includes an innovative approach to calculating ERR as the crack length approaches zero.

Fatigue of Unidirectional Cord-Rubber Composites

1999 ◽  
Vol 27 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Y. Liu ◽  
Z. Wan ◽  
Z. Tian ◽  
X. Du ◽  
J. Jiang ◽  
...  
Keyword(s):  
Damage Accumulation ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Constant Load ◽  
Testing System ◽  
Rubber Composites ◽  
Cycle Frequency ◽  
Periodic Loading ◽  
Fatigue Damage Accumulation ◽  
Rubber Composite

Abstract A fatigue testing system is established with which the real-time recording of stress, strain, temperature, and hysteresis loss of rubbers or cord-rubber composite specimens subjected to periodic loading or extension can be successfully carried out. Several problems are connected with the experimental study of the fatigue of rubber composites. In constant extension cycling, the specimen becomes relaxed because of the viscoelasticity of rubber composites, and the imposed tension-tension deformation becomes complex. In this method, the specimen is unlikely to fail unless the imposed extensions are very large. Constant load cycling can avoid the shortcomings of constant extension cycling. The specially designed clamps ensure that the specimen does not slip when the load retains a constant value. The Deformation and fatigue damage accumulation processes of rubber composites under periodic loading are also examined. Obviously, the effect of cycle frequency on the fatigue life of rubber composites can not be ignored because of the viscoelasticity of constituent materials. The increase of specimen surface temperature is relatively small in the case of 1 Hz, but the temperature can easily reach 100°C at the 8 Hz frequency. A method for evaluating the fatigue behavior of tires is proposed.

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