Fatigue Behaviour of Notched Ti-6Al-4V in Inert Environment

2011 ◽  
Vol 488-489 ◽  
pp. 502-505 ◽  
Author(s):  
Sergio Baragetti ◽  
Stefano Cavalleri ◽  
Federico Tordini
Keyword(s):  
Titanium Alloy ◽  
Fatigue Life ◽  
Fatigue Limit ◽  
Fatigue Behaviour ◽  
Nacl Solution ◽  
Fracture Surfaces ◽  
Inert Environment ◽  
Paraffin Oil ◽  
Step Loading ◽  
Complete Fracture

This work focuses on the fatigue behaviour of notched Ti-6Al-4V titanium alloy in inert environment. V-notched flat samples were cycled under axial fatigue (R = 0.1) under inert conditions by immersion in paraffin oil. A step-loading technique was used to determine the fatigue limit at the complete fracture for a constant fatigue life of 2×105load cycles. The results were compared with previous data obtained with tests carried out in air and 3.5 wt.% NaCl solution. Fracture surfaces were examined under stereoscopic microscope.

Load and Environmental Effects on the Corrosion Behavior of a Ti6Al4V Alloy

2012 ◽  
Vol 525-526 ◽  
pp. 501-504 ◽  
Author(s):  
Sergio Baragetti ◽  
Alessandro Medolago
Keyword(s):  
Titanium Alloy ◽  
Experimental Tests ◽  
Fatigue Tests ◽  
Methanol Solution ◽  
Nacl Solution ◽  
Static Loads ◽  
Aggressive Environment ◽  
Inert Environment ◽  
Paraffin Oil ◽  
Static Mechanical

This paper focuses on the static mechanical behavior of Ti-6Al-4V titanium alloy when exposed to several aggressive environments. Flat samples, with very light notches (i.e.Kt= 1.16), were tested under static loads, in inert environment and aggressive solutions: the samples gage sections were exposed to air and immerged in a NaCl solution (3.5%) and in a methanol solution (95%). The results of this experimental tests were analyzed and then compared with previous data coming from fatigue tests, carried out in paraffin oil, air, 3.5 wt.% NaCl, and in a methanol solution (95%), with the intent to decouple the effect of the alternating load and of the aggressive environment.

Measurement on Scale-Induced Fatigue Behaviour for Railway Axle

2008 ◽  
Vol 44-46 ◽  
pp. 65-70 ◽  
Author(s):  
Yong Xiang Zhao ◽  
Bing Yang ◽  
Ming Fei Feng
Keyword(s):  
Fatigue Life ◽  
Carbon Steel ◽  
Fatigue Limit ◽  
Fatigue Behavior ◽  
Fatigue Behaviour ◽  
Railway Axle ◽  
Material Fatigue ◽  
Lz50 Steel ◽  
The Difference

Transferring of fatigue behavior is investigated from material to structure for Chinese railway LZ50 axle carbon steel. S-N data in mid-fatigue life range and fatigue limit data of smooth small specimens are applied for material fatigue behavior. Real axles and similar smooth bigger specimens were tested with respect to fatigue limits. The data of real axles reveal the difference between material and a special structure. And the data of similar specimens play a role of bridge to connect material and material structures. Probabilistic transferring relations are deduced by the data from material, to similar specimens, and then to structures at the fatigue limit phase. Structural probabilistic S-N curves are obtained by the material fatigue behavior to extend the transferring relations to entire fatigue life range. Determinations of the fatigue behavior of the groove of LZ50 steel axle indicate availability of the present investigation.

The Behavior at Corrosion and Fatigue of the Aluminum Alloy, Coated with a Cobalt Base Alloy, Deposited by Thermal Spraying in Electric Arc

2015 ◽  
Vol 809-810 ◽  
pp. 584-589
Author(s):  
Stefan Lucian Toma ◽  
Iulian Ionita ◽  
Lucian Eva ◽  
Costică Bejinariu ◽  
Bogdan Istrate ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
Base Alloy ◽  
Fatigue Cracks ◽  
Thermal Spraying ◽  
Fatigue Behaviour ◽  
Electric Arc ◽  
Nacl Solution

The present investigation has been conducted in order to study the fatigue and corrosion fatigue behaviour of an aluminium alloy (99,5%Al) substrate coated with a 106 MXC deposited by thermal spraying in electric arc. It has been determined that the deposition of such a coating on the aluminum substrate gives rise to significant gains in fatigue life in comparison with the uncoated substrate, when testing is carried out both in air and in a 3,5 wt.% NaCl solution. It has been shown that during testing in air, the fatigue gain ranges between ~131 and 186%, depending on the maximum alternating stress applied to the material. Larger fatigue gains are associated with low alternating stresses. Also, when fatigue testing is conducted in the NaCl solution, the gain in fatigue resistance varies between ~124 and 159%. Fatigue cracks have been observed to initiate at the coating surface and then grow towards the substrate after propagating through the entire coating thickness. Although in the present work residual stresses were not measured, it is believed that the gain in fatigue life of the coating–substrate system is due to the presence of compressive residual stresses within the coating which hinder fatigue crack propagation. The deposition of the coating does not give rise to significant changes in the static mechanical properties and hardness of the aluminum alloy substrate.

Influence of Stresses below the Fatigue Limit on Fatigue Life

2014 ◽  
Vol 224 ◽  
pp. 45-50 ◽  
Author(s):  
Grzegorz Szala
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Fatigue Limit ◽  
Quantitative Assessment ◽  
Loading Conditions ◽  
Constant Amplitude ◽  
Variable Amplitude ◽  
Slip Bands ◽  
Step Loading ◽  
Variable Stresses

According to the performed analysis of fatigue phenomena occurring in metals, the effects of fatigue appear in the form of lines and slip bands under loading conditions producing variable stresses with values below the fatigue limit of these metals. It is commonly accepted that variable stresses with constant amplitude of values below 0.4 of the fatigue limit do not cause plastic strain in grains (lines and slip bands), thus they do not affect the fatigue life. This study is an attempt of quantitative assessment of the influence of stresses with values below the fatigue limit on fatigue life by using tests with programed two-step loading (variable-amplitude). Tests were performed with the use of C45 steel specimens.

Fatigue Behaviour of Notched PVD-Coated Titanium Components

2007 ◽  
Vol 348-349 ◽  
pp. 313-316 ◽  
Author(s):  
Sergio Baragetti ◽  
Luca Lusvarghi ◽  
F. Pighetti Mantini ◽  
Federico Tordini
Keyword(s):  
Titanium Alloy ◽  
Fatigue Limit ◽  
Fatigue Behaviour ◽  
Bending Tests ◽  
Cross Section Area ◽  
Section Area ◽  
Minimum Cross Section ◽  
Surface Notch ◽  
Rotating Bending ◽  
Pvd Film

In this paper the fatigue behaviour of Ti-6Al-4V alloy coated with a TiN arc-deposited PVD film was studied. Rotating bending tests (R = -1) were carried out on standard “hourglass” specimens to evaluate the fatigue limit at 200000 load cycles. Conventional and notched (120° Vnotch transversal to the rotating axis at the minimum cross section area) specimens were tested, both coated and uncoated, to investigate the effect of the coating on the fatigue limit of the titanium alloy, with and without the surface notch. Fracture surfaces were observed by SEM. The coating did not improve the titanium alloy fatigue life.

scholarly journals Influence of turning tool wear on the surface integrity and anti-fatigue behavior of Ti1023

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110112
Author(s):  
Li Xun ◽  
Wang Ziming ◽  
Yang Shenliang ◽  
Guo Zhiyuan ◽  
Zhou Yongxin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Plastic Deformation ◽  
Titanium Alloy ◽  
Fatigue Life ◽  
Tool Wear ◽  
Surface Integrity ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Machined Surface ◽  
Deformation Layer

Titanium alloy Ti1023 is a typical difficult-to-cut material. Tool wear is easy to occur in machining Ti1023, which has a significant negative effect on surface integrity. Turning is one of the common methods to machine Ti1023 parts and machined surface integrity has a direct influence on the fatigue life of parts. To control surface integrity and improve anti-fatigue behavior of Ti1023 parts, it has an important significance to study the influence of tool wear on the surface integrity and fatigue life of Ti1023 in turning. Therefore, the effect of tool wear on the surface roughness, microhardness, residual stress, and plastic deformation layer of Ti1023 workpieces by turning and low-cycle fatigue tests were studied. Meanwhile, the influence mechanism of surface integrity on anti-fatigue behavior also was analyzed. The experimental results show that the change of surface roughness caused by worn tools has the most influence on anti-fatigue behavior when the tool wear VB is from 0.05 to 0.25 mm. On the other hand, the plastic deformation layer on the machined surface could properly improve the anti-fatigue behavior of specimens that were proved in the experiments. However, the higher surface roughness and significant surface defects on surface machined utilizing the worn tool with VB = 0.30 mm, which leads the anti-fatigue behavior of specimens to decrease sharply. Therefore, to ensure the anti-fatigue behavior of parts, the value of turning tool wear VB must be rigorously controlled under 0.30 mm during finishing machining of titanium alloy Ti1023.

Variability in Fatigue Life of Near-α Titanium Alloy IMI 834

2021 ◽  
Author(s):  
Litton Bhandari ◽  
Jalaj Kumar ◽  
I. Balasundar ◽  
Amit Arora
Keyword(s):  
Titanium Alloy ◽  
Fatigue Life ◽  
Imi 834

Fatigue Behaviour of Dented Pipes Under Internal Pressure: A Numerical-Experimental Approach

2018 ◽  
Author(s):  
Mario A. Polanco-Loria ◽  
Håvar Ilstad
Keyword(s):  
Fatigue Life ◽  
Internal Pressure ◽  
Fatigue Behavior ◽  
Crack Depth ◽  
Fatigue Behaviour ◽  
Experimental Methodology ◽  
Experimental Program ◽  
Metal Loss ◽  
Life Predictions ◽  
Dent Depth

This work presents a numerical-experimental methodology to study the fatigue behavior of dented pipes under internal pressure. A full-scale experimental program on dented pipes containing gouges were achieved. Two types of defects were studied: metal loss (plain dent) and sharp notch. Both defects acting independently reduce the fatigue life performance but their combination is highly detrimental and must be avoided. We did not find a severity threshold (e.g. dent depth or crack depth) where these defects could coexist. In addition, based on numerical analyses we proposed a new expression for stress concentration factor (SCF) in line with transversal indentation. This information was successfully integrated into a simple fatigue model where the fatigue life predictions were practically inside the window of experimental results.

The Structure and Mechanical Properties of VT23 Welded Joints with Surface Layer Modified by Ultrasonic Mechanical Forging

2017 ◽  
Vol 743 ◽  
pp. 264-268 ◽  
Author(s):  
Anastasia Smirnova ◽  
Yury Pochivalov ◽  
Victor Panin ◽  
Anatoly Orishich ◽  
Aleksandr Malikov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Fatigue Life ◽  
Welded Joints ◽  
Experimental Tests ◽  
Relaxation Property ◽  
Surface Layers ◽  
Β Phase ◽  
Fatigue Life Test ◽  
Vt23 Titanium Alloy

The structure and mechanical properties of welded joints of VT23 titanium alloy received by method of laser welding after modifying the surface layers by ultrasonic mechanical forging (Treatment 1 and Treatment 2) were investigated. The experimental tests have revealed that the Treatment 2 provides a multiple increase in the relaxation property in fatigue life test. The formation of nonuniform distribution of vanadium, chromium and molybdenum in the welded joint increases the strength and, at the same time, the brittleness of β-phase. Mechanical treatment of the surface layers in the second mode provides a multiple increase in ductility up to 13%, in the as-received condition up to 9.9%. In consequence of plastic deformation, the β-phase intensity reduces twice with Treatment 2 which is related to its clustering. As follows from a presented data, the fatigue life of the VT23 titanium alloy has increased more than threefold.

scholarly journals Low-cycle fatigue behaviour of laser welded high-strength steel DOMEX 700 MC

2018 ◽  
Vol 157 ◽  
pp. 05013 ◽  
Author(s):  
Peter Kopas ◽  
Milan Sága ◽  
František Nový ◽  
Bohuš Leitner
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
High Strength Steel ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
High Strength ◽  
Fatigue Behaviour ◽  
Total Strain Amplitude ◽  
Cycle Fatigue ◽  
Fatigue Life Analysis

The article presents the results of research on low cycle fatigue strength of laser welded joints vs. non-welded material of high-strength steel DOMEX 700 MC. The tests were performed under load controlled using the total strain amplitude ɛac. The operating principle of the special electro-mechanic fatigue testing equipment with a suitable clamping system was working on 35 Hz frequency. Fatigue life analysis was conducted based on the Manson-Coffin-Basquin equation, which made it possible to determine fatigue parameters. Studies have shown differences in the fatigue life of original specimens and laser welded joints analysed, where laser welded joints showed lower fatigue resistance. In this article a numerical analysis of stresses generated in bending fatigue specimens has been performed employing the commercially available FEM-program ADINA.

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