5 results on '"Pingdi Ren"'
Search Results
2. Molecular dynamics simulation of grain size effect on friction and wear of nanocrystalline zirconium
- Author
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Zhu Kehao, Zhang Xiaoyu, Pingdi Ren, Gen Li, and Yuan Xinlu
- Subjects
Zirconium ,Materials science ,Mechanical Engineering ,chemistry.chemical_element ,Grain size effect ,02 engineering and technology ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,Nanocrystalline material ,Grain size ,Surfaces, Coatings and Films ,Molecular dynamics ,020303 mechanical engineering & transports ,0203 mechanical engineering ,chemistry ,Grain boundary ,Composite material ,0210 nano-technology ,Nanoscopic scale ,Diamond tool - Abstract
In this study, molecular dynamics simulation was conducted to investigate the frictional behaviors between diamond tool and zirconium (Zr) substrates at the nanoscale. The effects of grain size on friction and wear were discussed under different sliding velocities. The simulation results showed that the friction forces had similar variation tendencies under different sliding velocities. Besides, the friction responses were stronger at high sliding velocities because of the atomic adhesion while the ploughing effect was more obvious at slower sliding velocity. Moreover, both the friction forces and the wear amounts increased with the decrease in the average grain sizes of the substrates. To explain this phenomenon, the internal mechanism was investigated by using the dislocation extract algorithm and the atomic displacement analyses. The results showed that the [0001]-oriented single crystalline substrate was prone to form continuous dislocation structures moving tangentially along the sliding direction due to the characteristic of Zr's slip systems, whereas grain boundaries conducted the deformation further into the polycrystalline substrates, increasing the contact areas and causing atomic accumulation in front, both resulted in stronger friction responses and wear. Accordingly, with the decrease in average grain sizes, the substrates experienced more severe subsurface damage and the deformation mechanism of nanocrystalline Zr had evolved from dislocation emission to grain boundary rotation and sliding.
- Published
- 2020
3. Experimental study of the fretting wear behavior of Inconel 690 alloy under alternating load conditions
- Author
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Jianhua Liu, Zhang Xiaoyu, Pingdi Ren, Minhao Zhu, Run Du, Zhen-bing Cai, Jinfang Peng, and Yuan Xinlu
- Subjects
Materials science ,Mechanical Engineering ,Alloy ,Delamination ,Fretting ,02 engineering and technology ,Surfaces and Interfaces ,engineering.material ,021001 nanoscience & nanotechnology ,Surfaces, Coatings and Films ,Fretting wear ,020303 mechanical engineering & transports ,0203 mechanical engineering ,engineering ,Tube (fluid conveyance) ,Composite material ,0210 nano-technology ,Inconel - Abstract
This study investigated the fretting wear behavior of the nuclear power material Inconel 690 alloy. An improved PLINT high-temperature fretting tester was used on an Inconel 690 tube against a 1Cr13 cylinder at different temperatures (25 ℃ and 300 ℃) under alternating load conditions. The fretting-wear mechanism and the kinetic characteristic of Inconel 690 alloy were analyzed. Results showed that the fretting running behavior was closely related to the normal excitation frequency. In parallelogram shaped Ft– D curves, the friction fluctuates periodically, and accordingly the fretting was running in the slip regime. The steady-state friction force at room temperature in air was higher than that at 300 ℃. Moreover, the damage behavior of the fretting for Inconel 690 alloy strongly depended on the normal load, displacement amplitude, temperature, and excitation frequency in atmospheric environment. A superposition effect of fretting wear behavior was discovered because of the combined effect of alternating normal and tangential forces; thus, delamination became more significant. Abrasive wear and delamination were the major mechanisms in Inconel 690 alloy at room temperature in ambient air. The dominant mechanisms at 300 ℃ were the abrasive wear, oxidation wear, and delamination.
- Published
- 2018
4. Study on the fretting maps of Zircaloy-4 alloy against Inconel 718 alloy
- Author
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Gen Li, Zhang Qiang, Pingdi Ren, Minhao Zhu, Zhang Xiaoyu, Yuan Xinlu, and Jian Pu
- Subjects
Materials science ,Mechanical Engineering ,Alloy ,Zirconium alloy ,Fretting ,02 engineering and technology ,Surfaces and Interfaces ,Slip (materials science) ,engineering.material ,021001 nanoscience & nanotechnology ,Surfaces, Coatings and Films ,Abrasion (geology) ,Cracking ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Mechanics of Materials ,engineering ,Adhesive wear ,Composite material ,0210 nano-technology ,Inconel - Abstract
Fretting wear tests of Zircaloy-4 alloy against Inconel 718 alloy were conducted on a fretting wear rig. The contact state and fretting running characteristics of Zircaloy-4 alloy were investigated. The running condition fretting map of Zircaloy-4 alloy presents three regimes, namely, partial slip regime, mixed slip regime, and gross slip regime. Slight degradation was observed in the partial slip regime. In the mixed slip regime, adhesive wear of the stick zone and oxidation wear of the slip zone are the main damage mechanisms, and cracking was observed at the stick-slip boundary. Severe material detachment due to wear is predominant in the gross slip regime, and the main damage mechanisms are adhesion, plastic deformation, surface fatigue, frictional oxidation and abrasion.
- Published
- 2021
5. Experimental Study of the Fretting Wear Behavior of Incoloy 800 Alloy at High Temperature
- Author
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Zhang Xiaoyu, Jianhua Liu, Minhao Zhu, Zhen-bing Cai, Jinfang Peng, and Pingdi Ren
- Subjects
Materials science ,Mechanical Engineering ,Metallurgy ,Alloy ,Abrasive ,Boiler (power generation) ,Fretting ,02 engineering and technology ,Surfaces and Interfaces ,engineering.material ,021001 nanoscience & nanotechnology ,Cross contact ,Surfaces, Coatings and Films ,Normal load ,Fretting wear ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Mechanics of Materials ,engineering ,0210 nano-technology ,Incoloy - Abstract
The fretting wear behavior of the nuclear power material Incoloy 800 was investigated in this study. A PLINT high-temperature fretting tester was used on an Incoloy 800 cylinder against a 304SS cylinder at vertical cross contact under different temperatures (25, 300, and 400°C). During testing, a normal load of 80 N was applied, and the displacement amplitudes ranged from 2 to 40 µm. The fretting wear mechanism at high temperatures and the kinetic character of the materials of the Incoloy 800 steam generator tube were analyzed. Results showed that the fretting running regimes varied little with ncreasing temperature, and some microcracks were observed in both the mixed fretting regime (MFR) and the partial slip regime (PSR) at high temperatures. Slight abrasive wear and microcracks were the main wear mechanisms of the Incoloy 800 alloy in PSR, whereas those in the MFR and the gross slip regime were oxidative wear, abrasive wear, and delamination.
- Published
- 2017
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