scholarly journals The Evolution of Fretting Wear Behavior and Damage Mechanism in Alloy 690TT with Cycle Number

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2417 ◽  
Author(s):  
Long Xin ◽  
Yongming Han ◽  
Ligong Ling ◽  
Weidong Zhang ◽  
Yonghao Lu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Laser Scanning ◽  
Wear Behavior ◽  
Ion Beam ◽  
Fatigue Cracking ◽  
Damage Mechanism ◽  
Fretting Wear ◽  
Partial Slip ◽  
Stick Slip ◽  
Cycle Number

The evolution of fretting wear behavior and damage mechanism in Alloy 690TT with cycle number was investigated via laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM), focus ion beam (FIB), and transmission electron microscopy (TEM). The results showed that the fretting running status underwent a transition from partial slip and mixed stick-slip to final gross slip with the transformation of Ft–D curves from the ellipse to the parallelogram. The coefficient of friction (COF) experienced three drops throughout the fretting process, which indicated the transformation from high-friction wear to low-friction wear. The first drop was due to the transition from two-body to three-body contact. The second and third drops were mainly related to the evolution of the glaze layer from a localized distribution to completely covering the whole contact surface. The competition between fretting induced fatigue cracking (FIF) and fretting induced wear (FIW) ran through the entire fretting wear process. Before the 1.2 × 104th cycle, the fatigue crack growth was faster than wear, and FIF won the competition. As the fretting cycle continued to increase, the wear velocity was obviously faster than that of FIF, which indicated that FIW defeated FIF. The tribologically transformed structure (TTS) participated in the competition between FIF and FIW. The gain boundaries and dislocations in the TTS were a suitable pathway for crack initiation and propagation and oxygen permeation.

scholarly journals The Effect of Displacement Amplitude on Fretting Wear Behavior and Damage Mechanism of Alloy 690 in Different Gaseous Atmospheres

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5778
Author(s):  
Long Xin ◽  
Lanzheng Kang ◽  
Weiwei Bian ◽  
Mengyang Zhang ◽  
Qinglei Jiang ◽  
...  
Keyword(s):  
Wear Behavior ◽  
Displacement Amplitude ◽  
Fretting Wear ◽  
Partial Slip ◽  
Wear Volume ◽  
Stick Slip ◽  
Slip Regime ◽  
Mixed Regime ◽  
Alloy 690 ◽  
Strong Adhesion

The effect of displacement amplitude on fretting wear behavior and damage mechanisms of alloy 690 in air and nitrogen atmospheres was investigated in detail. The results showed that in air, the friction coefficient gradually increased with the increase in displacement amplitude which conformed to the universal law. In nitrogen, however, it had the highest point at the displacement amplitude of 60 μm due to very strong adhesion. Whether in air or nitrogen, the wear volume gradually increased with the increase in displacement amplitude. The wear volume in air was larger than that in nitrogen except at 30 μm. At 30 μm, the wear volume in air was slightly smaller. With an increase in displacement amplitude, a transformation of fretting running status between partial slip, mixed stick-slip, and final gross slip occurred along with the change of Ft-D curves from linear, to elliptic, to, finally, parallelogrammical. Correspondingly, the fretting regime changed from a partial slip regime to a mixed regime to a gross slip regime. With the increase in displacement amplitude, the transition from partial slip to gross slip in nitrogen was delayed as compared with in air due to the strong adhesion actuated by low oxygen content in a reducing environment. Whether in air or nitrogen, the competitive relation between fretting-induced fatigue and fretting-induced wear was prominent. The cracking velocity was more rapid than the wear. Fretting-induced fatigue dominated at 30 μm in air but at 30–60 μm in nitrogen. Fretting-induced wear won the competition at 45–90 μm in air but at 75–90 μm in nitrogen.

Fretting wear behavior of thermal-oxidation on titanium alloy in air and vacuum atmosphere

2021 ◽  
pp. 2150135
Author(s):  
Liangliang Sheng ◽  
Xiangtao Deng ◽  
Hao Li ◽  
Yuxuan Ren ◽  
Guoqing Gou ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Titanium Alloy ◽  
Thermal Oxidation ◽  
Wear Behavior ◽  
Fretting Wear ◽  
Partial Slip ◽  
Ti6al4v Titanium Alloy ◽  
Slip Regime ◽  
Air Atmosphere ◽  
Vacuum Atmosphere

In this work, an in-situ XPS analysis test combined self-designed high precision fretting wear tester was carried out to study the fretting wear behavior and the resulting tribo-oxidation of thermal-oxidation film on Ti6Al4V titanium alloy under the varied working atmosphere. The fretting-induced tribo-oxidation under the air and vacuum ([Formula: see text] Pa) environment was analyzed and its response on the resulting fretting wear resistance and damage mechanism was discussed. Results show that the working environment plays a significant role in the formation of tribo-oxidation and then determining the fretting wear resistance. Thermal-oxidation film in the vacuum atmosphere shows a better fretting wear resistance than that in the air atmosphere for all fretting regimes, except for partial slip regime (PSR) where there is an equivalent fretting wear resistance. Compared with the substrate Ti6Al4V titanium alloy, the thermal-oxidation film in the vacuum atmosphere performs a good protection for titanium alloy, especially for slip regime (SR), but not applied for air atmosphere.

scholarly journals Fretting Wear Behavior and Damage Mechanisms of Inconel X-750 Alloy in Dry Contacts

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Ibrohim A. Rustamov ◽  
Ozoda Sh. Sabirova ◽  
Zixi Wang ◽  
Yuming Wang
Keyword(s):  
Wear Behavior ◽  
Normal Load ◽  
Fretting Wear ◽  
Partial Slip ◽  
Test Duration ◽  
Material Transfer ◽  
Friction Forces ◽  
Frictional Properties ◽  
Load Tests ◽  
Oxidation Mechanisms

Tribological behavior of the Inconel X-750 alloy disk subjected to fretting against the GCr15 steel ball was investigated in an ambient laboratory air with relative humidity of 55–65%. A high-frequency oscillating Optimol SRV 4 tribometer was employed to execute dry fretting tests in the partial and gross slip regimes under constant 100 N normal load. Tests were carried out for 10, 30, and 90 minutes, and the friction forces vs. displacement amplitudes were monitored during the test duration. Posttest examinations were conducted utilizing advanced tools such as 3D optical surface profiler, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). The main objective was to obtain wear scar evolutions, frictional properties, and degradation mechanisms under the different running conditions over time. It was found that fretting wear behaviors of friction pairs were strongly influenced by fretting regimes. Degradation evolutions were greatly influenced by fretting time during partial slip regimes, i.e., evolving from asperity deformation and slight damage to the fatigue crack and material transfer. However, the combination of adhesive, abrasive, delamination, and wear oxidation mechanisms was repeated during the entire gross slip fretting process.

Cracking Induced by Fretting of Aluminium Alloys

1997 ◽  
Vol 119 (1) ◽  
pp. 36-42 ◽  
Author(s):  
Z. R. Zhou ◽  
L. Vincent
Keyword(s):  
Aluminium Alloys ◽  
Small Amplitude ◽  
Crack Nucleation ◽  
Normal Load ◽  
Fatigue Cracking ◽  
Fretting Fatigue ◽  
Fretting Wear ◽  
Partial Slip ◽  
Material Loss ◽  
Main Effects

Fretting-wear and fretting-fatigue loadings can both result in wear (material loss) and in crack nucleation and propagation (fatigue process). This paper deals with cracking induced by small amplitude displacements in the case of aeronautic aluminium alloys. The two sets of fretting maps are introduced: running condition fretting map is composed of partial slip (sticking), mixed fretting and gross sliding regime; material response fretting map is associated with two macro-degradation modes. Crack nucleation and propagation are analysed for every fretting regime. The mixed fretting regime appeared most detrimental with regards to fatigue cracking. Slip amplitude and normal load main effects discussed for fretting wear can be used to justify the fatigue limit decrease often obtained for fretting fatigue experiments.

A Novel Three-Dimensional Finite Element Model to Simulate Third Body Effects on Fretting Wear of Hertzian Point Contact in Partial Slip

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Arman Ahmadi ◽  
Farshid Sadeghi
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Three Dimensional ◽  
Point Contact ◽  
Fretting Wear ◽  
Partial Slip ◽  
Wear Particles ◽  
Third Body ◽  
Stick Slip ◽  
The Third

Abstract In this investigation, a finite element (FE) model was developed to study the third body effects on the fretting wear of Hertzian contacts in the partial slip regime. An FE three-dimensional Hertzian point contact model operating in the presence of spherical third bodies was developed. Both first bodies and third bodies were modeled as elastic–plastic materials. The effect of the third body particles on contact stresses and stick-slip behavior was investigated. The influence of the number of third body particles and material properties including modulus of elasticity, hardening modulus, and yield strength were analyzed. Fretting loops in the presence and absence of wear particles were compared, and the relation between the number of cycles and the hardening process was evaluated. The results indicated that by increasing the number of particles in contact, more load was carried by the wear particles which affect the wear-rate of the material. In addition, due to the high plastic deformation of the debris, the wear particles deformed and took a platelet shape. Local stick-slip behavior over the third body particles was also observed. The results of having wear debris with different material properties than the first bodies indicated that harder wear particles have a higher contact pressure and lower slip at the location of particles which affects the wear-rate.

scholarly journals Cyanobacterial calcification in modern microbialites at the submicrometer-scale

2013 ◽  
Vol 10 (2) ◽  
pp. 3311-3339 ◽  
Author(s):  
E. Couradeau ◽  
K. Benzerara ◽  
E. Gérard ◽  
I. Estève ◽  
D. Moreira ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cell Morphology ◽  
Laser Scanning ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Advanced Stages

Abstract. The search for microfossils in the geological record has been a long-term challenge. Part of the problem comes from the difficulty of identifying such microfossils unambiguously, since they can be morphologically confused with abiotic biomorphs. One route to improve our ability to correctly identify microfossils consists in studying fossilization processes affecting bacteria in modern settings. We studied the initial stages of fossilization of cyanobacterial cells in modern microbialites from Lake Alchichica (Mexico), a Mg-rich hyperalkaline crater lake (pH 8.9) hosting currently growing stromatolites composed of aragonite [CaCO3] and hydromagnesite [Mg5(CO3)4(OH)2 × 4(H2O)]. Most of the biomass associated with the microbialites is composed of cyanobacteria. Scanning electron microscopy analyses coupled with confocal laser scanning microscopy observations were conducted to co-localize cyanobacterial cells and associated minerals. These observations showed that cyanobacterial cells affiliating to the order Pleurocapsales become specifically encrusted within aragonite with an apparent preservation of cell morphology. Encrustation gradients from non-encrusted to totally encrusted cells spanning distances of a few hundred micrometers were observed. Cells exhibiting increased levels of encrustation along this gradient were studied down to the nm-scale using a combination of focused ion beam (FIB) milling, transmission electron microscopy (TEM) and scanning transmission X-ray microscopy (STXM) at the C, O and N K-edges. Two different types of aragonite crystals were observed: one type was composed of needle-shaped nano-crystals growing outward from the cell body with a crystallographic orientation perpendicular to the cell wall, and another type was composed of larger crystals that progressively filled the cell interior. Organic matter (OM), initially co-localized with the cell, decreased in concentration and dispersed away from the cell while crystal growth occurred. As encrustation developed, OM progressively disappeared, but remaining OM showed the same spectroscopic signature. In the most advanced stages of fossilization, only the textural organization of the two types of aragonite recorded the initial cell morphology and spatial distribution.

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