scholarly journals A review on the recent advances concerning the fatigue performance of titanium alloys for orthopedic applications

2021 ◽  
Author(s):  
Leonardo Contri Campanelli
Keyword(s):  
Medical Devices ◽  
Fatigue Behavior ◽  
Fatigue Performance ◽  
Fatigue Properties ◽  
Second Phase ◽  
Ti Alloys ◽  
Recent Advances ◽  
Porous Oxide ◽  
Orthopedic Applications ◽  
Surface Discontinuities

AbstractThis article presents a review on recent advances in the fatigue behavior of Ti alloys, especially the main commercial compositions for orthopedic applications. In the case of well‐known Ti–6Al–4V alloy, the major concern is related to the effect of the surface modification necessary to improve the osseointegration. The introduction of surface discontinuities due to the growth of a porous oxide layer, or the roughness development, may severely affect the fatigue performance depending on the level of alteration. In the case of additive manufactured Ti–6Al–4V, the fatigue response is also influenced by inherent defects of as‐built parts. Regarding the recently developed metastable β alloys, information about the fatigue properties is still scarce and mainly related to the effect of second phase precipitates, which are introduced to optimize the mechanical properties. The fatigue behavior of the Ti alloys is complex, as is their microstructure, and should not be neglected when the alloys are being developed or improved to be applied in medical devices.

scholarly journals Effect of Microstructure on Fatigue Properties of Several Ti-Alloys for Aerospace Application

2020 ◽  
Vol 321 ◽  
pp. 04015
Author(s):  
A. El-Chaikh ◽  
A. Danzig ◽  
D. Muenter
Keyword(s):  
Heat Treatment ◽  
Cross Sections ◽  
Volume Fraction ◽  
Fatigue Behavior ◽  
Slight Modification ◽  
Fatigue Properties ◽  
Ti Alloys ◽  
Wide Range ◽  
Flight Controls ◽  
Electron Microscopes

A wide range of available Ti-alloys is used at Liebherr-Aerospace Lindenberg GmbH for several aeronautical applications in flight controls and landing gear systems. For these applications, the mechanical properties of conventionally manufactured Ti-alloys (α+β, near β) as well as additive manufactured Ti-alloy were optimized. Modification of the heat treatment parameters of a near-β titanium alloy leads to optimization of the hardening process of large cross-sections. This modification allows the adjustment of an optimum volume fraction of the primary α-phase resulting in enhancing of the elongation, fracture toughness and fatigue properties. For a fatigue critical forging part from (α+β)-alloy a slight modification of the chemical composition combined with an additional heat treatment step during the forging process was performed. The adjusted microstructure of the modified process exhibits better fatigue behavior when compared to the conventional microstructure. Ti6Al4V parts produced by Additive Manufacturing, printed with optimized parameters and followed by heat treatment will result in reasonable fatigue properties in all printing directions, reducing the anisotropy of the printed parts. These improvements bring Liebherr-Aerospace Lindenberg GmbH in the position to adapt the used titanium alloys for the needs in a wide range. For the evaluation of the microstructure, light and scanning electron microscopes were used. Furthermore a model described in the “Metallic Materials Properties Development and Standardization” (MMPDS) was modified and used for the evaluation of the fatigue results.

Investigation on Fatigue Performance of TC4 Alloy by Laser Shock Processing with Different Processing Parameters

2011 ◽  
Vol 464 ◽  
pp. 552-555
Author(s):  
Kai Yu Luo ◽  
Feng Ze Dai ◽  
L. Zhang ◽  
J.W. Zhong ◽  
Hai Bing Guan
Keyword(s):  
Fatigue Behavior ◽  
Processing Parameters ◽  
Fatigue Performance ◽  
Fatigue Properties ◽  
Processing Parameter ◽  
Laser Shock Processing ◽  
Bending Fatigue ◽  
Three Point Bending ◽  
Tc4 Alloy ◽  
Shock Processing

In the present investigation, the effects of processing parameter on three-point bending fatigue pergormance of TC4 alloy are examined, particular emphasis is devoted to the question of appropriate LSP processing parameters for improving the fatigue properties. Based on cyclic deformation and stress/life (S/N) fatigue behavior, it was found that there was the optimal shock number of overlapped spots for three-point bending fatigue pergormance of TC4 alloy. By comparing with the as-received specimen, the fatigue performance of TC4 alloy has the most obvious improvement by LSP with two impacts.

Flexural fatigue performance of hybrid composite laminates based on E-glass and polypropylene fibers

2018 ◽  
Vol 32 (2) ◽  
pp. 228-247 ◽  
Author(s):  
MA Abd El-Baky ◽  
MA Attia
Keyword(s):  
Temperature Rise ◽  
Volume Fraction ◽  
Fatigue Behavior ◽  
Fatigue Performance ◽  
Fatigue Properties ◽  
Measured Temperature ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Flexural Fatigue ◽  
Reinforced Composite

An experimental investigation has been conducted to understand the effect of water aging on flexural fatigue performance of unidirectional polypropylene (PP)-glass (G) fiber–reinforced epoxy composites. Test specimens were fabricated using hand lay-up process with a constant total fiber volume fraction. The effects of the reinforcement hybridization, hybrid configuration, and stacking sequences on S–N curves were investigated. Deflection-controlled flexural fatigue tests with a frequency of 25 Hz at zero mean stress have been conducted. A 20% reduction of the initial applied moment was taken as a failure criterion. In the first stage, the flexural fatigue properties of un-aged composite specimens were studied in ambient temperature. In the second stage, flexural fatigue properties were investigated after a preliminary aging step in distilled water for 350 days. The specimen surface temperature rise was measured to ensure that there is no early damage happened in the tested specimens. Results indicated that the hybridization of PP fiber–reinforced composite with G fiber improves its flexural fatigue resistance but increase water uptake. Inter-intraply hybrid laminate with G-fiber layers at the specimen outer faces and PP-fiber layers in the specimen core exhibits the most favorable flexural fatigue behavior, that is, the highest cost ratio and the specific fatigue endurance strength. The water-sorption step induced a significant decrease in fatigue properties of the fabricated specimens. The highest measured temperature rise was observed to be about 9°C for G fiber–reinforced composite.

scholarly journals Quantitative Analysis of Inclusion Engineering on the Fatigue Property Improvement of Bearing Steel

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 476 ◽  
Author(s):  
Chao Gu ◽  
Min Wang ◽  
Yanping Bao ◽  
Fuming Wang ◽  
Junhe Lian
Keyword(s):  
Fatigue Life ◽  
Quantitative Analysis ◽  
Critical Size ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Property ◽  
Bearing Steel ◽  
Fatigue Properties ◽  
Bearing Steels ◽  
Inclusion Distribution

The fatigue property is significantly affected by the inner inclusions in steel. Due to the inhomogeneity of inclusion distribution in the micro-scale, it is not straightforward to quantify the effect of inclusions on fatigue behavior. Various investigations have been performed to correlate the inclusion characteristics, such as inclusion fraction, size, and composition, with fatigue life. However, these studies are generally based on vast types of steels and even for a similar steel grade, the alloy concept and microstructure information can still be of non-negligible difference. For a quantitative analysis of the fatigue life improvement with respect to the inclusion engineering, a systematic and carefully designed study is still needed to explore the engineering dimensions of inclusions. Therefore, in this study, three types of bearing steels with inclusions of the same types, but different sizes and amounts, were produced with 50 kg hot state experiments. The following forging and heat treatment procedures were kept consistent to ensure that the only controlled variable is inclusion. The fatigue properties were compared and the inclusions that triggered the fatigue cracks were analyzed to deduce the critical sizes of inclusions in terms of fatigue failure. The results show that the critical sizes of different inclusion types vary in bearing steels. The critical size of the spinel is 8.5 μm and the critical size of the calcium aluminate is 13.5 μm under the fatigue stress of 1200 MPa. In addition, with the increase of the cleanliness of bearing steels, the improvement of fatigue properties will reach saturation. Under this condition, further increasing of the cleanliness of the bearing steel will not contribute to the improvement of fatigue property for the investigated alloy and process design.

Very High Cycle Fatigue Behavior and Life Prediction of a Low Strength Weld Metal at Moderate Temperature

2011 ◽  
Author(s):  
Ming-Liang Zhu ◽  
Fu-Zhen Xuan ◽  
Zhengdong Wang
Keyword(s):  
Crack Initiation ◽  
Weld Metal ◽  
Room Temperature ◽  
Fatigue Behavior ◽  
Fatigue Properties ◽  
Dissimilar Welding ◽  
Initiation Mechanism ◽  
Metallic Inclusions ◽  
Low Strength ◽  
Very High

The fatigue properties of a low strength weld metal in a dissimilar welding joint in high cycle and very high cycle regimes were investigated by fully reversed axial tests in air at room temperature and 370°C. A clear duplex S-N curve existed as a result of the transition of fatigue failure mode from surface-induced failure to internal-induced failure at 370°C, while the S-N curve was continuously decreased at room temperature. A new model was successfully proposed to predict fatigue life, and interpret the crack initiation modes transition from surface inclusion to interior inclusion. It was concluded that cracks were initiated by competition among non-metallic inclusions, welding pores and discontinuous microstructures in high cycle regime. While in the very high cycle regime, non-metallic inclusions were the dominant crack initiation mechanism which depended on stress level, inclusion size as well as inclusion depth.

Evaluation of High Cycle Fatigue Properties of Double Side Welded AISI 321 Plates Using GTAW Process for Pressure Vessels

2021 ◽  
Author(s):  
Mohan Kumar S ◽  
A. Rajesh Kannan ◽  
Pramod R. ◽  
Pravin Kumar N ◽  
Nallathambi Siva Shanmugam ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Fatigue Behavior ◽  
Fatigue Behaviour ◽  
Pressure Vessels ◽  
Fatigue Properties ◽  
Dendritic Microstructure ◽  
Gas Tungsten Arc ◽  
Gtaw Process ◽  
Fatigue Rupture ◽  
Aisi 321

Abstract Titanium stabilized AISI 321 material (UNS S32100) is generally preferred in the pressure vessel industry as they are not sensitive to intergranular corrosion. In critical applications, the fatigue behaviour of weld seams are amongst the most stringent requirements. The microstructural characteristics and fatigue performance of double side welded AISI 321 plate having 6 mm thickness were evaluated in this work. AISI 321 was welded with Double side-gas tungsten arc welding (DS-GTAW) process. The fatigue behavior was examined under a loading ratio of 0.1 for two different specimens: Base metal (BM) and Weld metal (WM). Monotonic tensile results show the improved tensile properties of WM compared to BM samples. The fatigue strength of WM (332.6 MPa) was 25% higher than that of BM (265.7 MPa) specimen and is attributed to the increase in ferrite volume along with dendritic microstructure. The change in the fraction of low angle grain boundaries (LABs) and high angle grain boundaries (HABs) improved the tensile and fatigue properties. The stress amplitudes influenced the degree of striations in the BM and WM. Final fracture surfaces were characterized with dimples and micro-voids, revealing the ductile mode of fatigue fracture. The fatigue rupture surfaces of BM and WM samples at different stress regimes are discussed.

Effect of Heat Treatment on Very High Cycle Fatigue Properties of TC4

2021 ◽  
Vol 881 ◽  
pp. 3-11
Author(s):  
Bo Han Wang ◽  
Li Cheng ◽  
Xun Chun Bao
Keyword(s):  
Heat Treatment ◽  
High Cycle Fatigue ◽  
Treatment Method ◽  
Fatigue Performance ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Α Phase ◽  
Very High Cycle Fatigue ◽  
Significant Difference ◽  
Very High

The bimodal, equiaxed and Widmanstatten microstructures of TC4 titanium alloy were obtained through different heat treatment processes. The content of primary α phase in the bimodal and equiaxed microstructures was measured to be about 40% and 90%, and the average size was about 9.4μm and 7.9 μm. Three types of microstructure fatigue S-N curves are obtained, which are successively descending type, single-platform descending type and infinite life type. The order of very high cycle fatigue performance is Widmanstatten>equiaxed>bimodal, but the anti-fretting fatigue performance of Widmanstatten is the worst. The grain refinement makes the fatigue performance of the equiaxed better than that of the bimodal. The second process is determined as the best heat treatment method. There is no significant difference in the life of the crack propagation stage. The very high cycle fatigue life mainly depends on the crack initiation stage. In the bimodal and the equiaxed, the crack initiates in the primary α phase of the subsurface, and the crack in the Widmanstatten initiates in the coarse α 'grain boundary of the subsurface.

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