Effect of Temperature Induced by Laser Irradiation Processing on Fatigue Damage Repairing for Copper Thin Film

2013 ◽  
Vol 750-752 ◽  
pp. 2074-2077
Author(s):  
Lu Wang ◽  
De Guang Shang ◽  
Chong Gang Ren ◽  
Yu Bo Guo ◽  
Tao Chen
Keyword(s):  
Thin Film ◽  
Temperature Field ◽  
Laser Irradiation ◽  
Fatigue Damage ◽  
Simulation Method ◽  
Optical Microscope ◽  
Laser Surface ◽  
Effect Of Temperature ◽  
Copper Thin Film ◽  
Before And After

Based on laser irradiation processing experiment for repairing damaged copper thin film specimens, the effect of temperature field induced by pulsed laser surface irradiation on fatigue damage repairing of copper thin film was studied by numerical simulation method. First the temperature field of copper thin film after laser irradiation was analyzed by ANSYS under different pulse energies and pulse numbers. Then the surface morphologies of copper thin film specimens were observed by optical microscope before and after laser surface irradiation. The results showed that laser irradiation processing has a better effect on fatigue damage repairing when the temperature induced by laser surface irradiation reaches about 1200 °C. A slightly melted morphology on the surface of copper thin film was observed in this case. In addition, except for the full healing of fatigue damage, the total fatigue life was increased about 2 times at the nominal stress level of 120MPa.

The Study on the Variation of Friction Coefficient of Flank Lock Type Precision Locknut at the Different Tightening Speed

2014 ◽  
Vol 541-542 ◽  
pp. 588-591 ◽  
Author(s):  
Chih Ming Chen ◽  
Chin Huang Sun
Keyword(s):  
Friction Coefficient ◽  
Surface Morphology ◽  
Fatigue Damage ◽  
Axial Force ◽  
Optical Microscope ◽  
Test Machine ◽  
Experimental Setting ◽  
Thread Surface ◽  
Before And After

The study investigated the variation of friction coefficient of a vertical assembly of flank lock type precision locknut at the different tightening speed by a torque and axial force test machine. The tightening speed is set at 4rpm, 6rpm and 8rpm, respectively. The lubricant is a type of 2TML. Surface morphology was observed before and after the test via an optical microscope. The experiment proceeded to five preloads to test and took the sixth as the experimental setting through the ISO 2320 specification. The study observed the variation of friction coefficient at the different tightening speed under a preload. The results show that the friction coefficient tends to be smaller when the tightening speed becomes faster. The increase of friction coefficient associates with the increase of anti-loosening ratio. For the surface morphology, it was found that the seat surface and the thread surface of the locknut generates the reaming, scraping and fatigue damage after the repeated tightening and loosening test.

scholarly journals Numerical simulation and analysis of the temperature effect on the fission of concrete

2019 ◽  
Vol 23 (5 Part A) ◽  
pp. 2713-2720 ◽  
Author(s):  
Guangcheng Liu
Keyword(s):  
Numerical Simulation ◽  
Temperature Field ◽  
Numerical Calculation ◽  
Temperature Control ◽  
Surface Stress ◽  
Simulation Method ◽  
Concrete Surface ◽  
Effect Of Temperature ◽  
Insulation Material ◽  
Maximum Surface

In order to further improve the crack resistance of concrete engineering, a numerical simulation method is constructed to study the effect of temperature on the fission of concrete. Based on the finite element method, the mathematical model is constructed, and the numerical calculation and image display are used to simulate and analyze the engineering problems. The temperature sensor is used to observe the whole variation law of typical temperature field, and the temperature of concrete entering and pouring is obtained. Thus, the temperature control real-time automatic acquisition system is set up. According to the temperature field and temperature stress distribution rules, the ideal temperature control curve model of concrete is proposed. Finally, the numerical calculation and experiment of the model are carried out. The results show that the maximum surface stress level decreases in varying degrees after different surface insulation measures are taken, and if the thermal insulation material?s ? ? 10 kJ/m2h?, the maximum surface stress of concrete can be reduced to 0.06~0.14 MPa. In this paper, it is shown that the negative effect of the large diurnal temperature difference on concrete surface insulation can be controlled.

Some early history of replica techniques for electron microscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1076-1077
Author(s):  
Robert M. Fisher
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Optical Microscope ◽  
Early History ◽  
Bulk Materials ◽  
Thin Sections ◽  
Transmission Electron ◽  
Reflected Light ◽  
History Of ◽  
Electron Microscopes

By 1940, a half dozen or so commercial or home-built transmission electron microscopes were in use for studies of the ultrastructure of matter. These operated at 30-60 kV and most pioneering microscopists were preoccupied with their search for electron transparent substrates to support dispersions of particulates or bacteria for TEM examination and did not contemplate studies of bulk materials. Metallurgist H. Mahl and other physical scientists, accustomed to examining etched, deformed or machined specimens by reflected light in the optical microscope, were also highly motivated to capitalize on the superior resolution of the electron microscope. Mahl originated several methods of preparing thin oxide or lacquer impressions of surfaces that were transparent in his 50 kV TEM. The utility of replication was recognized immediately and many variations on the theme, including two-step negative-positive replicas, soon appeared. Intense development of replica techniques slowed after 1955 but important advances still occur. The availability of 100 kV instruments, advent of thin film methods for metals and ceramics and microtoming of thin sections for biological specimens largely eliminated any need to resort to replicas.

CVD copper thin film deposition using (α-methylstyrene)Cu(I)(hfac)

2001 ◽  
Vol 11 (PR3) ◽  
pp. Pr3-553-Pr3-560 ◽  
Author(s):  
W. Zhuang ◽  
L. J. Charneski ◽  
D. R. Evans ◽  
S. T. Hsu ◽  
Z. Tang ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Copper Thin Film

EVALUATION OF TRIBOTECHNICAL PROPERTIES OF THE COATING OBTAINED BY ELECTRIC SPARK HARDENING

2020 ◽  
Vol 4 (141) ◽  
pp. 157-163
Author(s):  
IL’YA ROMANOV ◽  
◽  
ROMAN ZADOROZHNIY
Keyword(s):  
Wear Resistance ◽  
Reference Sample ◽  
Optical Microscope ◽  
Research Purpose ◽  
Tribotechnical Properties ◽  
Uncoated Surface ◽  
Before And After ◽  
Materials Used ◽  
Friction Track

When applying coatings using various methods on the surfaces of moving parts that work in joints, it is important to make sure that the coatings are strong and wear-resistant in order to return them to their original resource. All existing hardening technologies and materials used to perform coatings have their own characteristics, therefore, the quality of the resulting coatings can be judged only after specific tests. (Research purpose) The research purpose is in evaluating the properties of the coating obtained by the method of electric spark hardening, and its ability to resist friction and mechanical wear. (Materials and methods) Authors conducted tests on the basis of the "Nano-Center" center for collective use. A coating was applied on the BIG-4M unit with a VK-8 hard alloy electrode, tribological properties were evaluated on a CSM Instruments TRB-S-DE-0000 tribometer, the width of the friction track was measured after the test using an inverted OLYMPUS gx51 optical microscope, and samples were weighed before and after the test on a VLR-200 analytical balance. Conducted research in accordance with GOST 23.224-86 and RD 50-662-88 guidelines. (Results and discussion) The article presents performed tests on the run-in and wear resistance of the coating. The samples were worked on with a step-by-step increase in the load. During the tests, the friction force was drawed on the diagram. Authors compared the results with the reference sample, an uncoated surface. (Conclusions) The resulting coating has better run-in and wear resistance compared to the standard, and the increase in wear resistance in dry friction conditions is very significant.

scholarly journals Recent advances in characterizing the “bee” structures and asphaltene particles in asphalt binders

2020 ◽  
Vol 13 (6) ◽  
pp. 697-706
Author(s):  
Yuhong Wang ◽  
Kecheng Zhao ◽  
Fangjin Li ◽  
Qi Gao ◽  
King Wai Chiu Lai
Keyword(s):  
Near Field ◽  
Asphalt Binder ◽  
Optical Microscope ◽  
Asphalt Binders ◽  
Zero Shear Viscosity ◽  
Surface Features ◽  
Asphaltene Content ◽  
Scanning Transmission ◽  
Before And After ◽  
Binder Aging

AbstractThe microscopic surface features of asphalt binders are extensively reported in existing literature, but relatively fewer studies are performed on the morphology of asphaltene microstructures and cross-examination between the surface features and asphaltenes. This paper reports the findings of investigating six types of asphalt binders at the nanoscale, assisted with atomic force microscopy (AFM) and scanning transmission electron microscopy (STEM). The surface features of the asphalt binders were examined by using AFM before and after being repetitively peeled by a tape. Variations in infrared (IR) absorbance at the wavenumber around 1700 cm−1, which corresponds to ketones, were examined by using an infrared s-SNOM instrument (scattering-type scanning near-field optical microscope). Thin films of asphalt binders were examined by using STEM, and separate asphaltene particles were cross-examined by using both STEM and AFM. In addition, connections between the microstructures and binder’s physicochemical properties were evaluated. The use of both microscopy techniques provide comprehensive and complementary information on the microscopic nature of asphalt binders. It was found that the dynamic viscosities of asphalt binders are predominantly determined by the zero shear viscosity of the corresponding maltenes and asphaltene content. Limited samples also suggest that the unique bee structures are likely related to the growth of asphaltene content during asphalt binder aging process, but more asphalt binders from different crude sources are needed to verify this finding.

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