In Situ Observation of Microwedge Effect on Liquid Lubrication

2004 ◽  
Vol 126 (4) ◽  
pp. 690-696 ◽  
Author(s):  
Sy-Wei Lo ◽  
Bo-Qi Zhou ◽  
Ching-Feng Fang ◽  
Yu-Sheng Lu
Keyword(s):  
Elastic Deformation ◽  
Average Velocity ◽  
Contact Region ◽  
Hydrodynamic Pressure ◽  
The Other ◽  
In Situ Observation ◽  
Sliding Velocity ◽  
Surface Separation ◽  
Tool Surface

The influence of the minute elastic deformation of tool surface, named the “microwedge,” on the asperity crushing in liquid lubrication is investigated experimentally. The microwedge plays a role so dominant that although increasing the average velocity of the lubricant can alleviate the asperity deformation; such efforts will be overwhelmed by the microwedge effect if the relative sliding velocity between tool and workpiece is also enhanced concurrently. For all roughness patterns, the asperities show multidirectional expansions of the contact region; an important feature of the microwedge effect. The microwedge effect also creates distributions of surface separation and hydrodynamic pressure neither expected nor explainable by the other models.

scholarly journals Lubrication Analysis of Micro-Dimple Textured Die Surface by Direct Observation of Contact Interface in Sheet Metal Forming

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 917 ◽  
Author(s):  
Shimizu ◽  
Kobayashi ◽  
Vorholt ◽  
Yang
Keyword(s):  
Metal Forming ◽  
High Speed ◽  
Sliding Friction ◽  
Flow Analysis ◽  
Hydrodynamic Pressure ◽  
Observation System ◽  
In Situ Observation ◽  
Two Phase ◽  
Micro Dimple

: To investigate the underlying mechanism of the effects of surface texturing on lubricated sliding friction in the metal forming operation, an in-situ observation system using transparent silica glass dies and a high speed recording camera was newly developed. To correlate the dimensional parameters of micro-dimple textured structures and tribological properties in the metal forming operation, the in-situ observation was performed during bending with the ironing process of the stainless steel sheet with a thickness of 0.1 mm. The lubrication behavior were compared between the different lubricant viscosities and the micro-dimple textures with different diameters of 10 µm, 50 µm, 100 µm fabricated by using femto-/pico-second laser processing. As a result, the textured die with dimple diameters of 10 µm and 50 µm showed the lubricant flow transferred from one to the other dimples owing to the lubricant reservoir effect, while that of 100 µm indicated the less supply of the lubricant. However, the textured die with a dimple diameter of 10 µm demonstrated higher ironing force than that of 50 µm, due to the severe adhesion of work materials inside the dimple structures. Based on these experimental findings, the dimple size dependencies on lubricant reservoirs effects and the generation of the hydrodynamic pressure were discussed by correlating with the in-situ observation results, a fluid-flow analysis and a laminar two-phase flow analysis using the finite element method.

scholarly journals Ultrasonic Bonding of Multi-Layered Foil Using a Cylindrical Surface Tool

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 505
Author(s):  
Arimoto ◽  
Sasaki ◽  
Doi ◽  
Kim
Keyword(s):  
Relative Motion ◽  
Cylindrical Surface ◽  
High Speed ◽  
Image Correlation ◽  
In Situ Observation ◽  
Copper Sheet ◽  
Bonding Material ◽  
Ultrasonic Bonding ◽  
Tool Surface

A cylindrical tool was applied for ultrasonic bonding of multi-layered copper foil and a copper sheet to prevent damage to the foil during bonding. The strength of the joints bonded with the cylindrical tool was comparable to that of the joints bonded with a conventional knurled tool. The effect of the cylindrical surface tool on bondability was investigated thorough relative motion behaviors between the tool surface and the bonding materials, as well as on bond microstructure evolution. The relative motion was visualized with in-situ observation using a high-speed camera and digital image correlation. At shorter bonding times, relative motions occurred at the bonding interfaces of the foil and the copper sheet. Thereafter, the relative motion between the tool and the bonding material became predominant owing to bond formation at the bonding interface, resulting in a macroscopic plastic flow in the bonded region. This relative motion damaged the foil in knurled tool bonding, and the cylindrical tool achieved bonding without any damage.

scholarly journals In Situ Observation of Epitaxial Growth during Evaporative Simultaneous Crystallization from Aqueous Electrolytes in Droplets

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1122
Author(s):  
Frederico M. Penha ◽  
Fábio R. D. Andrade ◽  
Amanda S. Lanzotti ◽  
Paulo F. Moreira Junior ◽  
Gustavo P. Zago ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Complex Systems ◽  
Epitaxial Growth ◽  
The Other ◽  
In Situ Observation ◽  
Aqueous Electrolytes ◽  
Industrial Crystallization ◽  
Ternary Solutions ◽  
Almost All

In this study, crystallization phenomena were investigated by real-time in situ observation of seeded droplets under evaporation using a self-developed hot-stage platform. Ternary solutions at eutonic conditions at 25 °C were investigated for the following systems: NaCl–KCl–H2O, NaCl–CaSO4–H2O, and NaCl–Na2SO4–H2O. Evidence of epitaxial growth was found for aqueous NaCl–KCl and aqueous NaCl–Na2SO4. Sodium chloride nucleated and grew epitaxially upon the other substrates in a larger proportion compared with the inverse. This observation could be related to the higher solubility, and consequently higher residual supersaturation of NaCl regarding the other components. Hopper-like NaCl crystals developed in almost all systems. The results may help devise strategies to control particle morphologies and purity in industrial crystallization from complex systems.

Solid-State Amorphization in a Ti/B Multilayer

1991 ◽  
Vol 49 ◽  
pp. 904-905
Author(s):  
Alan F. Jankowski ◽  
Mark A. Wall ◽  
Daniel M. Makowiecki
Keyword(s):  
Thin Films ◽  
Solid State ◽  
The Other ◽  
Heat Of Mixing ◽  
In Situ Observation ◽  
Multilayered Structures ◽  
Adjacent Layer ◽  
Isothermal Anneal ◽  
State Amorphization

Thin films of pure crystalline metals, that have a negative heat of mixing, are known to amorphize. Solid-state amorphization reactions are possible to study using multilayered structures. The amorphization reaction is typically observed in multilayered structures in which one layer of the pair is crystalline and the adjacent layer or interface is amorphous, as in Ni/Zr and Cu/Y. The reaction progresses via a low temperature isothermal anneal (at several hundred degrees centigrade) in which one species preferentially diffuses into the other. Recently, in-situ observation of solid-state amorphization in a completely crystalline Ni/Ti multilayer indicates that nucleation of the amorphous phase occurs at incoherent crystalline interlayer boundaries. (The completely crystalline as-deposited structure was achieved by ensuring thermalization of the sputtered neutrals.) The progression of solidstate amorphization in Ti-B is examined using the multilayered configuration.

Development of UHVTEM with UHV compatible goniometer and specimen-treatment chamber for surface studies

1994 ◽  
Vol 52 ◽  
pp. 496-497
Author(s):  
Y. Kondo ◽  
H. Kobayashi ◽  
Y. Ishibashi ◽  
T. Kasai ◽  
H. Nunome ◽  
...  
Keyword(s):  
Ultrahigh Vacuum ◽  
The Other ◽  
In Situ Observation ◽  
Surface Studies ◽  
Transmission Electron ◽  
New Type ◽  
Pre Treatment ◽  
Electron Microscopes ◽  
And Performance

JEOL has previously been involved in the development of various ultrahigh vacuum transmission electron microscopes (UHVTEM). Interest in UHVTEM is increasing, and for higher vacuum, higher resolution and specimen treatment capability, we have developed a new type of UHVTEM, the JEM- 2000FXVII. This paper reports the construction and performance of this new UHVTEM including a newly developed UHV compatible goniometer, specimen treatment chamber and various types of specimen heating holders.Figure 1 shows the overview of the JEM-2000FXVII with a specimen pre-treatment chamber (PTC) and UHV compatible goniometer. The PTC consists of two chambers: one for specimen treatment and the other for pre-evacuation. Specimen treatment is accomplished by using any of 7 attachment ports (six 70ϕ ICFs and a 152ϕ ICFs) in the PTC (Fig. 2). The PTC is attached directly to the TEM column and quick exchange of the specimen from PTC to column is thus possible. In-situ observation is also possible using the three attachment ports (70ϕ ICFs) in the column.

The effect of radiation-induced segregation on void swelling in electron-irradiated austenitic Fe-Cr-Ni-Ti-P Alloy

1990 ◽  
Vol 48 (4) ◽  
pp. 932-933
Author(s):  
H. Watanabe ◽  
T. Muroga ◽  
N. Yoshida
Keyword(s):  
Temperature Dependence ◽  
Electron Irradiation ◽  
Irradiation Temperature ◽  
The Other ◽  
Austenitic Steels ◽  
Nickel Concentration ◽  
In Situ Observation ◽  
Void Swelling ◽  
Radiation Induced

It has been reported that the void swelling in austenitic steels at higher temperatures is enhanced by a nickel depletion in matrix . The objective of the present study is to understand the effect of solute addition on void swelling, in association with microchemical changes, in austenitic steels during electron irradiation.Four types of model alloys (Fe-16Cr-17Ni, Fe-16Cr-17Ni-0.25Ti, Fe- 16Cr-17Ni-0.1P, Fe-16Cr-17Ni-0.25Ti-0.IP) and JPCA-2 were used in this study. Irradiation and in-situ observation were carried out with 1.0 MeV electrons utilizing JEM-1000 of HVEM Lab. Kyushu Univ.Fig. 1 shows the irradiation temperature dependence of nickel concentration in matrix after irradiated at 2 dpa. The ternary alloy and alloys containing phosphorus(or titanium) only show a strong nickel depletion in matrix due to nickel segregation to defect sinks. Our previous results about void swelling in these alloys showed that the temperature, where nickel depletion in matrix became prominent, corresponded to that of maxium void swelling. On the other hand, void swelling and the nickel depletion were not detected in Fe-16Cr-17Ni-0.25Ti-0.IP and JPCA-2.

In situ observation of the elastic deformation of a single epitaxial SiGe crystal by combining atomic force microscopy and micro x-ray diffraction

2009 ◽  
Vol 106 (10) ◽  
pp. 103525 ◽  
Author(s):  
M. S. Rodrigues ◽  
T. W. Cornelius ◽  
T. Scheler ◽  
C. Mocuta ◽  
A. Malachias ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Elastic Deformation ◽  
In Situ Observation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force

In Situ Observation of Catalyzed Gasification of Graphite by Nickel

1981 ◽  
Vol 39 ◽  
pp. 76-77
Author(s):  
R. T. K. Baker ◽  
R. D. Sherwood
Keyword(s):  
Objective Lens ◽  
In Situ Observation ◽  
Gas Flows ◽  
Catalytic Gasification ◽  
Television Camera ◽  
Viewing Screen ◽  
Fuels And Chemicals ◽  
Gasification Of Carbon ◽  
Transmission Microscope

The catalytic gasification of carbon at high temperature by microscopic size metal particles is of fundamental importance to removal of coke deposits and conversion of refractory hydrocarbons into fuels and chemicals. The reaction of metal/carbon/gas systems can be observed by controlled atmosphere electron microscopy (CAEM) in an 100 KV conventional transmission microscope. In the JEOL gas reaction stage model AGl (Fig. 1) the specimen is positioned over a hole, 200μm diameter, in a platinum heater strip, and is interposed between two apertures, 75μm diameter. The control gas flows across the specimen and exits through these apertures into the specimen chamber. The gas is further confined by two apertures, one in the condenser and one in the objective lens pole pieces, and removed by an auxiliary vacuum pump. The reaction zone is <1 mm thick and is maintained at gas pressure up to 400 Torr and temperature up to 1300<C as measured by a Pt-Pt/Rh 13% thermocouple. Reaction events are observed and recorded on videotape by using a Philips phosphor-television camera located below a hole in the center of the viewing screen. The overall resolution is greater than 2.5 nm.

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