scholarly journals The Effect of Milling Cooling Conditions on the Surface Integrity and Fatigue Behavior of the GH4169 Superalloy

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1179 ◽  
Author(s):  
Rufeng Xu ◽  
Yongxin Zhou ◽  
Xun Li ◽  
Shenliang Yang ◽  
Kangning Han ◽  
...  
Keyword(s):  
Surface Integrity ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Properties ◽  
Dry Milling ◽  
Wet Milling ◽  
Machined Surface ◽  
Side Milling ◽  
Cooling Conditions ◽  
Gh4169 Superalloy

The GH4169 superalloy has high strength at high temperatures. Cooling conditions have a major impact on the machined surface integrity, which further affects the fatigue properties of specimens of the GH4169 superalloy. The influence of cooling conditions on the surface integrity of the GH4169 superalloy is first studied during the side milling. Then, the effect of surface integrity under different cooling conditions on the fatigue behavior of specimens of the GH4169 superalloy is investigated by a standard tensile and tensile–mode fatigue testing. The results obtained show that surface roughness and the depth of the plastic deformation layer in wet milling and dry milling makes little difference, the surface microhardness rate in dry milling is slightly lower than that in wet milling, the surface tensile residual stress in dry milling is significantly higher than that in wet milling, and the fatigue behavior in dry milling is only about 50% of that in wet milling. In addition, the crack initiation of specimens of the GH4169 superalloy utilizing wet milling is on the subsurface, while that from dry milling is on the surface. Thus, cooling conditions have an important impact on the fatigue behavior of specimens of the GH4169 superalloy, and micro defects in dry milling are the main factors of decreasing of fatigue behavior of specimens of the GH4169 superalloy.

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.

scholarly journals Effect of machine hammer peening on the surface integrity of a ZnAl-based corrosion protective coating

2020 ◽  
Vol 318 ◽  
pp. 01008
Author(s):  
Alina Timmermann ◽  
Mohamed Abdulgader ◽  
Leif Hagen ◽  
Alexander Koch ◽  
Philipp Wittke ◽  
...  
Keyword(s):  
Corrosion Fatigue ◽  
Surface Integrity ◽  
Protective Coatings ◽  
Fatigue Behavior ◽  
Turbine Blades ◽  
Fatigue Properties ◽  
Machine Hammer Peening ◽  
Coated Surfaces ◽  
Thermally Sprayed ◽  
Hammer Peening

Thermally sprayed protective coatings are applied onto many mechanically stressed components such as support structures, shafts, turbine blades or heat exchangers. In addition to the static or cyclic load, a superimposition with corrosion processes occurs in many cases. Thermal sprayed ZnAl coatings are known for their performant corrosion protection properties. Within this context, the potential of ZnAl-based layer systems was analyzed regarding corrosion fatigue behavior. Therefore, a timeand cost-efficient testing strategy based on a corrosion-superimposed load increase procedure was used to estimate the effects of a corrosive attack during cyclic loading. The investigated coating systems were thermally sprayed and partially post-processed with a Machine Hammer Peening (MHP) operation. This treatment was identified as an appropriate technique for compressing and smoothing coated surfaces. The inter-relationships between the parametrization of the MHP process, the resulting surface integrity, and the estimated corrosion fatigue properties were analyzed. The investigations indicate a positive effect of MHP post-processing operations on the surface properties of the ZnAl-based coating system.

scholarly journals Analysis of the Influence of Surface Modifications on the Fatigue Behavior of Hot Work Tool Steel Components

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7324
Author(s):  
Thomas Wild ◽  
Timo Platt ◽  
Dirk Biermann ◽  
Marion Merklein
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Surface Integrity ◽  
Fatigue Behavior ◽  
Hot Forging ◽  
Surface Modifications ◽  
Bending Test ◽  
Fatigue Properties ◽  
Machining Processes ◽  
Residual Stress State

Hot work tool steels (HWS) are widely used for high performance components as dies and molds in hot forging processes, where extreme process-related mechanical and thermal loads limit tool life. With the functionalizing and modification of tool surfaces with tailored surfaces, a promising approach is given to provide material flow control resulting in the efficient die filling of cavities while reducing the process forces. In terms of fatigue properties, the influence of surface modifications on surface integrity is insufficiently studied. Therefore, the potential of the machining processes of high-feed milling, micromilling and grinding with regard to the implications on the fatigue strength of components made of HWS (AISI H11) hardened to 50 ± 1 HRC was investigated. For this purpose, the machined surfaces were characterized in terms of surface topography and residual stress state to determine the surface integrity. In order to analyze the resulting fatigue behavior as a result of the machining processes, a rotating bending test was performed. The fracture surfaces were investigated using fractographic analysis to define the initiation area and to identify the source of failure. The investigations showed a significant influence of the machining-induced surface integrity and, in particular, the induced residual stress state on the fatigue properties of components made of HWS.

Low Tension-Tension Cycle Fatigue Properties of 301 Stainless Steel Thin Sheets

2013 ◽  
Vol 351-352 ◽  
pp. 887-891
Author(s):  
Shi Ming Cui ◽  
Rui Dong Wang ◽  
Yong Jie Liu ◽  
Tao Long ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Stress Ratio ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Properties ◽  
Testing System ◽  
Loading Frequency ◽  
Thin Sheets ◽  
Cycle Fatigue ◽  
Low Tension

By using of a micro mechanical fatigue testing system, low tension-tension cycle fatigue properties of 301 stainless steel thin sheets with a thickness of 0.1 mm were studied. The effects of loading frequency and stress ratio were considered in the tests. The results show the S-N curves descend continuously in the low cycle regime. Cyclic σ-N curve was obtained according to the traditional fatigue theory. It agrees well with the experimental data, showing that the traditional fatigue research methods are also suitable to describe thin sheets in a certain extent. With the increase of loading stress ratio, the fatigue strength of thin sheets is increased. There is an evident effect of frequency on the fatigue behavior of the thin sheets.

scholarly journals In Vitro Fatigue Properties of Prototype Woven Vascular Prosthesis with Poly (trimethylene terephthalate) Filaments as Circumferential Yarns

2012 ◽  
Vol 7 (4) ◽  
pp. 155892501200700
Author(s):  
Ying Chen ◽  
Xin Ding ◽  
Yuling Li ◽  
Xueqian Zhao
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Vascular Prosthesis ◽  
Fatigue Properties ◽  
Vascular Prostheses ◽  
Initial Modulus ◽  
Before And After ◽  
Show Evidence ◽  
Improve Compliance

As far as we know, fatigue properties of woven vascular prosthesis with PTT filaments as circumferential yarns which could improve compliance due to their lower initial modulus and better elasticity had not yet studied. In this study viscoelastic properties of PTT filaments were studied and fatigue properties of woven vascular prostheses with PTT filaments as circumferential yarns were tested using an accelerated fatigue tester. The changes of each property before and after the fatigue testing show evidence of fatigue. It will be more evidence of fatigue with increasing fatigue cycles and PTT tubular samples show better fatigue behavior compared to PET tubular samples.

Effect of Cutting Fluid on Milling of Additively Manufactured Inconel 738LC

2021 ◽  
Vol 1027 ◽  
pp. 117-122
Author(s):  
Guan Hui Ren ◽  
Cong Zhou ◽  
Bi Zhang
Keyword(s):  
Electron Microscopy ◽  
Tool Wear ◽  
Surface Integrity ◽  
Laser Scanning ◽  
Sample Surface ◽  
Cutting Fluid ◽  
Surface Plastic ◽  
Dry Milling ◽  
Wet Milling ◽  
Inconel 738Lc

This study focuses on the effect of cutting fluid on sample surface integrity and tool wear in milling additively manufactured Inconel 738LC. Sample surface integrity and tool wear characterization was undertaken using scanning electron microscopy, backscatter electron microscopy, energy dispersive spectroscopy, laser scanning confocal microscopy, ultra-depth of field digital microscope system and digital display hardness tester. Compared with dry milling, wet milling not only provides an entirely different result on surface morphology, but also shows less surface plastic deformation, and smaller surface roughness. In addition, the tool wear mechanisms of wet milling are found to be different compared to dry milling.

High Cycle Fatigue Behavior of Normalized 0.15% C Steel under Tension-Compression and Torsion Loading

2008 ◽  
Vol 378-379 ◽  
pp. 29-38 ◽  
Author(s):  
Herwig Mayer ◽  
Snezana Stojanovic ◽  
Stefanie Stanzl-Tschegg ◽  
Bernhard Zettl
Keyword(s):  
Endurance Limit ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Properties ◽  
Cyclic Torsion ◽  
Cycling Frequency ◽  
Endurance Tests ◽  
Ultrasonic Fatigue ◽  
Small Cracks ◽  
Limit Stress

Fatigue properties of mild steel are investigated under cyclic tension-compression and cyclic torsion loading using ultrasonic fatigue testing equipment and cycling frequency of approx. 20 kHz. Both S-N curves show a distinct change of slope at about 107 cycles, and endurance limits determined at 107 and 109 cycles differ by less than their respective standard deviations. Endurance limit shear stress determined for cyclic torsion loading is about 60% of the tension-compression endurance limit stress, and the slopes of the S-N curves are comparable. Non-propagating cracks could be found in specimens, which did not fail within 109 cycles in torsion loading endurance tests. The endurance limit can be understood as maximum stress amplitude, where possibly formed small cracks do not propagate to failure.

Fatigue and Fracture Behavior of Porous TiNi Alloys

2014 ◽  
Vol 783-786 ◽  
pp. 591-596
Author(s):  
G. Ipek Nakaş ◽  
Emin Erkan Aşik ◽  
Bensu Tunca ◽  
Şakir Bor
Keyword(s):  
Endurance Limit ◽  
Fatigue Testing ◽  
Bone Ingrowth ◽  
Fatigue Behavior ◽  
Fatigue Properties ◽  
Compression Tests ◽  
Micro Cracks ◽  
Wide Range ◽  
Structural Applications ◽  
Application Fields

While the wide range of applications of TiNi alloys make them highly appealing due to their shape memory and superelasticity properties, production of TiNi in the porous form further enlarges their application fields. Porous TiNi alloys have been studied extensively for biomedical applications due to their elastic modulus similar to that of bone. Accordingly, TiNi 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 the scope of this study, fatigue behavior of TiNi foams, which were produced from prealloyed powders by Mg space holder technique, was examined via load controlled cyclic compression-compression tests. The endurance limit of the tested foams was taken as the stress level at which the specimens sustain their integrity without showing any sign of failure beyond 106cycles. TiNi foams with porosity contents in the range of 39-64 vol%, which is suitable for bone ingrowth, were determined to have an endurance limit ranging in between 26-89 MPa. On the other hand, fractography studies on the failed foams after fatigue testing revealed that the failure occurs by the coalescence of micro-cracks initiated from pore walls leading to macro-crack formation aligned at 45owith respect to the loading axis.

Cycling of Ultrafine-Grained Ti-6Al-4V ELI Alloy: Microstructural Changes and Enhanced Fatigue Limit

2008 ◽  
Vol 584-586 ◽  
pp. 827-832 ◽  
Author(s):  
Lilia R. Saitova ◽  
Heinz Werner Höppel ◽  
Matthias Göken ◽  
A.R. Kilmametov ◽  
Irina P. Semenova ◽  
...  
Keyword(s):  
Fatigue Limit ◽  
Equal Channel Angular Pressing ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Metallic Materials ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
High Structural Stability

Ti-6Al-4V ELI (extra low interstitials) was processed by equal channel angular pressing in order to obtain an ultrafine-grained (UFG) microstructure which is known to enhance the fatigue behavior of metallic materials. Fatigue properties of UFG Ti-6Al-4V ELI were studied by strain and stress controlled fatigue tests. UFG Ti-6Al-4V ELI shows an improvement of the fatigue behavior compared to conventional grain (CG) size counterpart. Microstructural investigations prior to and after fatigue testing confirm a high structural stability of the UFG material. Hence, the UFG alloy has a high potential for prospective use in biomedical and engineering applications.

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