scholarly journals Properties of Jet-Plated Ni Coating on Ti Alloy (Ti6Al4V) with Laser Cleaning Pretreatment

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 248
Author(s):  
Xiao Wang ◽  
Mingyang Xu ◽  
Zhanwen Wang ◽  
Lida Shen ◽  
Mingbo Qiu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Titanium Alloy ◽  
Energy Density ◽  
Oxide Layer ◽  
High Efficiency ◽  
Laser Energy ◽  
Laser Cleaning ◽  
Laser Energy Density ◽  
Wear Volume ◽  
Jet Electrodeposition

The surface mechanical properties of the Selective Laser Melting (SLM) formed Ti6Al4V samples were improved by adopting a novel laser cleaning pretreatment process combined with a jet electrodeposition process. This paper aimed to investigate the effects of different laser powers on the morphologies and adhesions of the nickel coatings. The advantages of the laser cleaning process are no grinding, no contact, high efficiency and environmental protection. The morphologies, adhesion, wear resistance, and hardness of the coatings were characterized. The results indicate that when the laser energy density reached 20% (4 J/cm2), the contaminations on the substrate and the oxide layer were removed and the crystalline grain of the coating was 15.3 nm. The shallow pits generated by laser burning increased the adhesion of the coatings. In addition, when the laser energy density increased to 6 J/cm2, a yellow oxide layer was produced on the surface of the cleaned titanium alloy. Moreover, the wear resistance of the titanium alloy after the nickel plating was improved. The wear volume was only 0.046 mm3, and the hardness increased to 1967.6 N/mm2.

Removal characteristics of shop-primer paint by laser energy density in Q-switching fiber laser cleaning

2020 ◽  
Vol 34 (07n09) ◽  
pp. 2040042
Author(s):  
Ji-Eon Kim ◽  
Myoung-Soo Han ◽  
Jong-Do Kim
Keyword(s):  
Energy Density ◽  
Fiber Laser ◽  
Oxide Layer ◽  
Base Metal ◽  
Steel Surface ◽  
Laser Energy ◽  
Laser Cleaning ◽  
Low Energy ◽  
Laser Energy Density ◽  
Q Switching

In this study, we performed laser cleaning using a Q-switching fiber laser to remove the shop-primer paint and the oxide layer. An analysis of the surface cleaned by laser was carried out at various energy densities. The results showed that the oxide layer on the steel surface was not removed at a relatively low energy density, whereas the base metal was damaged under excessive energy density. We confirmed that it was essential to select an appropriate energy density for efficiently removing only the paint and the oxide layer without damaging the base metal in laser cleaning.

Temperature Gradient and Heat Conduction of Titanium Alloy during Laser Welding

2010 ◽  
Vol 154-155 ◽  
pp. 42-45
Author(s):  
Ke Rong Zhang ◽  
Jian Xun Zhang
Keyword(s):  
Titanium Alloy ◽  
Heat Conduction ◽  
Liquid Phase ◽  
Energy Density ◽  
Temperature Gradient ◽  
Molten Pool ◽  
Solid Phase ◽  
Laser Energy ◽  
Laser Energy Density ◽  
Heating And Cooling

This paper set a numerical calculation model with local mesh refined for laser welding of titanium alloy applying body heat source model which can accurately describe the shape of keyhole and molten pool on laser welded joint. It calculated the change patterns of the temperature distribution and heat conduction in region of gas, liquid, and solid phase under different laser energy density on the stage of heating and cooling. The results showed that with the increase of the laser energy density t, the dimension of keyhole and molten pool, the temperature gradient and the duration of gas and liquid phase on the stage of heating and cooling are all expected to increase. Under the same laser energy density, temperature gradient has a maximum value in the region of gas phase, secondly is in liquid phase, and minimum in solid phase.

scholarly journals Improvement of Wear Resistance in Laser Shock-Peened Copper Contacts

2020 ◽  
Vol 58 (8) ◽  
pp. 560-565
Author(s):  
Donghyuck Jung ◽  
Changkyoo Park ◽  
Eun-Joon Chun ◽  
Yoon-Jun Kim
Keyword(s):  
Residual Stress ◽  
Wear Resistance ◽  
Energy Density ◽  
Laser Energy ◽  
Stress Test ◽  
Electrical Contact ◽  
Pure Copper ◽  
Surface Hardness ◽  
Laser Energy Density ◽  
Laser Shock

This study investigated the influence of laser shock peening without coating (LSPw/oC) on the degradation of copper electrical contacts. A theoretical calculation of the plastic-affected depth (PAD) induced by LSPw/oC was performed, based on the laser-induced plasma pressure along with the Hugoniot elastic limit of our LSPw/oC experimental conditions. The theoretical PAD was obtained approximately 650 µm from the surface for the LSPw/oC at the laser energy density of 5.3 GW/cm2. Various characterization methods such as the Vicker’s hardness test, residual stress test, and electron backscattered diffraction (EBSD) mapping indicated the PAD may play a significant role in laser induced effective depth for LSPw/oC. At a laser energy density of 5.3 GW/cm2, the laser shock-peened copper showed approximately double the surface hardness as compared to the pure copper. This was attributed to grain refinement, which was confirmed by measuring average grain sizes, and by observing mechanical twin structures from the EBSD analysis. Additionally, a compressive residual stress was induced down to the PAD but gradually switched to a tensile residual stress below PAD. The surface hardening effect conferred by LSPw/oC to the pure copper surface resulted in excellent wear resistance, i.e., a low coefficient of friction and wear loss. As a result, the contact exhibited lower electrical resistance following the fretting friction test compared to pure copper; this would result in a significant delay in electrical contact failure.

Influence of Laser Energy Density on Acquisition and Wear Resistance of Bionic Semisolid Unit of 40Cr Steel

2020 ◽  
Vol 29 (4) ◽  
pp. 2283-2295 ◽  
Author(s):  
Hui Li ◽  
Hong Zhou ◽  
Peng Zhang ◽  
Ti Zhou ◽  
Wei Su ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Energy Density ◽  
Laser Energy ◽  
Laser Energy Density ◽  
40Cr Steel

scholarly journals Research on mechanism and process of paint removal with pulsed fiber laser

2018 ◽  
Vol 189 ◽  
pp. 01008
Author(s):  
Xiaodi Zeng ◽  
Wenbin Qin ◽  
Jing Li ◽  
Zhiyong Wang
Keyword(s):  
Energy Density ◽  
Fiber Laser ◽  
Laser Energy ◽  
Steel Substrate ◽  
Paint Layer ◽  
Laser Cleaning ◽  
Laser Energy Density ◽  
Cleaning Efficiency ◽  
Pulsed Fiber Laser ◽  
Paint Removal

Compared with the traditional cleaning technology, laser cleaning, as a new type of industrial technology, has the advantages of high cleaning rate, green pollution-free and low cost. So laser cleaning is widely used in the fields of paint removal. This paper analyzes that the mechanism of paint removal and heat transfer process in the paint layer and substrate, also determines the process parameters of affect the laser paint removal. The removal of paint from steel substrate with fiber laser of frequency adjustable 20 to 500kHz at 1064nm is reported, researching impact that laser energy density,scanning speed and line width on the paint removal effect. The results show that, the 100μm paint layer can be removed completely while keeping the substrate undamaged with the laser energy density of 10.19J/cm2 and speed of 4200mm/s and width of 0.02mm. In order to get better results, the cleaning efficiency can be improved by increasing the power, speed and spot size under the right energy density.

scholarly journals Preliminary Laser Cleaning Studies of a Consolidated Prehistoric Basketry Coming from the Pile Building of Fiavè-Carera in the North-East of Italy

2006 ◽  
Vol 2006 ◽  
pp. 1-5 ◽  
Author(s):  
Romina Belli ◽  
Antonio Miotello ◽  
Paolo Mosaner ◽  
Laura Toniutti ◽  
Marta Bazzanella
Keyword(s):  
Energy Density ◽  
Material Removal ◽  
Laser Energy ◽  
Laser Cleaning ◽  
Original Surface ◽  
North East ◽  
The North ◽  
Cleaning Procedures ◽  
Krf Excimer Laser ◽  
Organic Deposits

In the archaeological field, some specific advantages are recognized to laser cleaning, like, for example, the absence of mechanical contacts with the sample. The cleaning procedures generally involve a multilayer structure (dust, dirty, organic deposits, and, in some cases, consolidant substances). In this work, prehistoric wood samples (found and consolidated in 1970s) have been laser irradiated (KrF excimer laser) in order to restore their original surface aspect. A certain amount of burned matter was also present. Samples came from a fragment of a prehistoric basketry found in the lake dwelling site of Fiavè-Carera, Trento, Italy (1500–1400 BC). It was observed that the laser cleaning effects are strictly dependent on the irradiation parameters (power density and number of pulses). Efficient material removal was possible by using appropriate energy density. Moreover, for lower laser energy density, special structures appeared on the surface of the consolidating substance that we attributed to heating-induced stresses on the consolidant surface.

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