scholarly journals Effect of Turning and Surface Polishing Treatments on Surface Integrity and Fatigue Performance of Nickel-Based Alloy GH4169

Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 549 ◽  
Author(s):  
Daoxia Wu ◽  
Dinghua Zhang ◽  
Changfeng Yao
Keyword(s):  
Surface Integrity ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Fatigue Properties ◽  
Small Surface ◽  
Axial Texture ◽  
Surface Polishing ◽  
Microhardness And Microstructure ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

In this paper, the effects of turning and surface polishing treatments on surface integrity and fatigue properties of superalloy GH4169 were investigated. Finish turning (FT), surface circumferential polishing treatment (TCP), surface oblique texture (TCPO), and surface axial texture (TCPA) were applied to GH4169 superalloy. The surface roughness, surface topography, residual stress, microhardness, and microstructure after different processes were studied. Rotating bending fatigue tests were carried out to investigate the effects of surface integrity and surface texture direction on the fatigue performance of GH4169. The experiments reveal that the TCPA specimens present the longest fatigue life of 15.01 × 104 cycles. By comparison with the FT, TCP, and TCPO specimens, the fatigue lives of TCPA specimens are increased by 134.2%, 183.7%, and 96.2%, respectively. Single crack initiation source is observed for TCPA specimen. It is mainly attributed to the small surface stress concentration factor and surface axial texture.

On the Effect of Electrodischarge Drilling on the Fatigue Life of Inconel 718

2014 ◽  
Vol 891-892 ◽  
pp. 1451-1456
Author(s):  
Elena Bassoli ◽  
Andrea Baldini ◽  
Andrea Gatto ◽  
Antonio Strozzi ◽  
Lucia Denti
Keyword(s):  
Fatigue Life ◽  
Inconel 718 ◽  
Metal Cutting ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Aerospace Applications ◽  
Rotating Bending Fatigue ◽  
Cutting Operation ◽  
Rotating Bending ◽  
Superposition Effect

Difficult-to cut-materials are associated with premature tool failure, most likely in the case of complex geometries and this shapes. However, Nickel-based alloys are commonly used in high-temperature and aerospace applications, where thin deep holes are often required. Then, the only viable manufacturing solution relies on non-contact processes, like electrodischarge (ED) drilling. Morphology of ED machined surfaces is significantly different than obtained by metal-cutting operation and is known to jeopardize fatigue strength, but the extent needs to be gauged and related to the process parameters. Aim of the paper is to study the effect of holes (0.8 mm diameter, aspect ratio 10) produced by ED drilling on the fatigue life of Inconel 718. Rotating bending fatigue tests are carried out on specimens drilled under two ED setups, as well as with a traditional cutting tool. Specimens free from holes are fatigued under the same conditions for comparison. Based on previous studies, extremal ED parameters are selected, giving best surface finish versus highest productivity. S-N curves show that the ED process causes a decrease of the fatigue resistance with respect to traditional drilling, whereas the effect of different ED setups is negligible. Maximum productivity can thus be pursued with no threat to fatigue performance. The fatigue limit variation is quantified by using the superposition effect principle: ED drilling causes an increase of the stress concentration factor around 25% if compared to traditional drilling. The macroscopic fatigue behavior is integrated with a study of the effects of the different drilling processes in the micro-scale, by means of a microstructural and fractographic analysis.

scholarly journals Effects of Case Depth and Notch Shape on the Rotating Bending Fatigue Properties of Carburized Steel

1980 ◽  
Vol 66 (3) ◽  
pp. 410-417 ◽  
Author(s):  
Tôru FURUKAWA ◽  
Shizuyo KONUMA ◽  
Hideyasu SAKANIWA ◽  
Tadashi KASUYA
Keyword(s):  
Case Depth ◽  
Fatigue Properties ◽  
Bending Fatigue ◽  
Carburized Steel ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

Fatigue Behaviour of DLC Coated Al 7075-T6 Alloy in an Aggressive Mixture

2014 ◽  
Vol 627 ◽  
pp. 81-84 ◽  
Author(s):  
Sergio Baragetti ◽  
Riccardo Gerosa ◽  
Francesco Villa
Keyword(s):  
High Performance ◽  
Contact Fatigue ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Structural Elements ◽  
Pvd Coatings ◽  
Bending Fatigue ◽  
Al 7075 ◽  
Rotating Bending Fatigue ◽  
Rotating Bending

7075-T6 aluminium alloy is commonly adopted in high performance structures and components. Its fatigue behaviour is however dramatically worsened by exposure to aggressive environments. The deposition of PVD coatings, which are commonly adopted to increase the surface properties of structural elements in terms of hardness, contact fatigue and wear resistance, could be beneficial also for the fatigue behaviour of a 7075-T6 substrate in an aggressive environment. In the present work, Diamond Like Carbon (DLC) PVD coated 7075-T6 specimens immersed in methanol have been analysed, by means of step-loading rotating bending fatigue tests (R = -1) at 2·105 cycles. Coated specimens were tested in laboratory air for comparison, and uncoated polished samples were studied in both the environments to obtain reference values. SEM micrographs of the fracture surfaces were taken to investigate the effects of the corrosive environment on the failure mechanism.

High Cycle Fatigue Properties of Duplex Stainless Steel in Air and 3.5% NaCl Solution

2015 ◽  
Vol 750 ◽  
pp. 114-120
Author(s):  
Shu Rong Yu ◽  
Wei Song ◽  
Shu Xin Li ◽  
Meng Kai
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
High Cycle Fatigue ◽  
Fatigue Properties ◽  
Cycle Fatigue ◽  
Ductile Mode ◽  
Bending Fatigue Test ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Austenite Grains

The high cycle fatigue of super duplex stainless steel of SAF 2507 was investigated by rotating bending fatigue test in both air and 3.5% NaCl environment. The results showed that there is no much reduction of the fatigue life in corrosive environment, which is 90% of the air fatigue strength. In air fatigue, failure happens in ductile mode with austenite grains having finer and straighter fatigue striations than ferrite grains. Width and spacing of striations vary with the orientation and locations when the second cracking occurs. It is not reliable to identify the phase by morphology of striations. In 3.5% NaCl environment, the fracture exhibits a mixed mode of cleavage and quasi-cleavage in ferrites and ductile in austenite grains.

Rotating bending fatigue properties of two case hardening steels after nitriding treatment

2013 ◽  
Vol 46 ◽  
pp. 539-545 ◽  
Author(s):  
Chao Zhou ◽  
Maoqiu Wang ◽  
Weijun Hui ◽  
Han Dong ◽  
Lei Wang ◽  
...  
Keyword(s):  
Fatigue Properties ◽  
Case Hardening ◽  
Bending Fatigue ◽  
Rotating Bending Fatigue ◽  
Rotating Bending
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