Molecular Dynamics Study of Laser and Plasma Nitriding of Titanium

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Hanjiang Yu ◽  
Tianya Tan ◽  
Wei Wu ◽  
Chao Tian ◽  
Ying An ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Power Density ◽  
Laser Power ◽  
Plasma Nitriding ◽  
Processing Parameters ◽  
Nitride Layer ◽  
Laser Power Density ◽  
Experimental Results ◽  
Good Qualitative Agreement ◽  
Scanning Velocity

The molecular dynamics (MD) method is successfully applied to simulate the nitridation of titanium by the mixing technology with laser and plasma. Based on the simulation, the influence of the processing parameters, such as the laser power density and the scanning velocity on the effective thickness of the nitride layer, was investigated. It was found that, for each scanning velocity, there is a laser power density range within which the higher laser power density has the beneficial effect for nitriding treatment. Comparing the simulation and experimental results shows that the calculated results are in good qualitative agreement with the experimental results.

Effects of Parameters on Surface Roughness of Metal Parts by Selective Laser Melting

2013 ◽  
Vol 834-836 ◽  
pp. 872-875 ◽  
Author(s):  
Qun Qin ◽  
Guang Xia Chen
Keyword(s):  
Surface Roughness ◽  
Power Density ◽  
Selective Laser Melting ◽  
Laser Power ◽  
Processing Parameters ◽  
Laser Power Density ◽  
Laser Melting ◽  
Scanning Velocity ◽  
Metal Parts ◽  
Overlap Ratio

The primary goal of this research is the effects of laser process parameters on surface roughness of metal parts built by selective laser melting. The main processing parameters used to control the surface roughness of melted layers are laser power, scanning velocity and overlap ratio. In our work, an orthogonal experimental design was employed to find the changing rules of the surface roughness through changing SLM processing parameters. The results show that the overlap ratio is the most important factor to affect the surface roughness. When the overlap ratio is below 50%, the surface roughness value of melted layers will decrease with laser power density increasing. When the overlap ratio is higher than or equal to 50%, the surface roughness value increases with the laser power density increasing. The optimal parameters of laser power 143W, scanning velocity 5m/min and overlap ratio 30% can be used to achieve melted layers with the best surface quality in our experiments, and the roughness value increases with slicing thickness increasing and the surface bias angle decreases.

Effect of Laser Power on the Microstructure of Ni-P Layer Deposited on Aluminum Substrate

2011 ◽  
Vol 686 ◽  
pp. 539-545
Author(s):  
Yue Yang ◽  
Jian Dong Hu
Keyword(s):  
Power Density ◽  
Laser Processing ◽  
Laser Power ◽  
Processing Parameters ◽  
Laser Power Density ◽  
Aluminum Substrate ◽  
Nickel Aluminum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Equilibrium Phases

Laser processing of Ni-P layer electroless deposited on aluminum substrate was carried out by Nd-YAG pulsed laser. Different laser processing parameters were selected. When lower laser power density was employed, the modified Ni-P layer was obtained, however, when employed laser power density increased, laser alloying of Ni-P layer with aluminum substrate occurred. The characteristic dendritic or lamellar microstructures were observed in the alloyed layer. The phase constituents of the alloyed zones determined by X-ray diffraction are consisted of nickel-aluminum intermetallic compounds NiAl, Al3Ni and Al3Ni2, as well as some non-equilibrium phases, depending on the employed laser power density.

The Effects of Laser Texturing Parameters on Wear Properties of Rollers with Fractal Geometry

2008 ◽  
Vol 375-376 ◽  
pp. 328-332
Author(s):  
Hong Bin Liu ◽  
Da Ping Wan ◽  
De Jin Hu
Keyword(s):  
Fractal Dimension ◽  
Wear Rate ◽  
Power Density ◽  
Fractal Geometry ◽  
Laser Power ◽  
Processing Parameters ◽  
Laser Power Density ◽  
Textured Surface ◽  
Laser Texturing ◽  
Fractal Parameters

The processing parameters of laser texturing are linked with the wear property of roller surface based on the relationship between the fractal parameters and surface roughness. The influence of laser power density, scanning speed and pulse width on the roughness is analyzed though experiments. The effect of fractal parameters on the wear rate of the roller is analyzed with fractal geometry model for wear prediction. Condition of achieving engineering surface with optimal fractal dimension is presented and the expression of the optimal fractal dimension is derived. It shows that the roughness of laser textured surface and normalized wear rate are mainly determined by laser power density and fractal dimension, respectively. Moreover, to get the textured surface with smallest nominal wear rate, processing parameters of laser texturing, especially the laser power density, should be controlled properly besides the material properties of the roller. The result will provide guidance for the processing.

scholarly journals Influence of Saturation Phenomena on Laser-Excited Atomic Fluorescence Flame Spectrometry

1973 ◽  
Vol 28 (2) ◽  
pp. 273-279
Author(s):  
J. Kühl ◽  
S. Neumann ◽  
M. Kriese
Keyword(s):  
Power Density ◽  
Laser Power ◽  
Atomic Emission ◽  
Equation Model ◽  
Laser Power Density ◽  
Atomic Level ◽  
Dye Laser ◽  
Atomic Fluorescence ◽  
Emission Flame ◽  
Flame Spectrometry

Using a simple rate equation model, the laser power density Ic necessary to reach 50% of the saturation limited population of the excited atomic level under typical flame conditions is calculated. For Na atoms aspirated into the flame a saturating power density for irradiation with a narrow dye laser line (bandwidth 0.033 Å) of Ic ~ 0.4 kW/cm2 was determined. With the aid of a dye laser with an appropriate laser power density, analytical curves for Na were measured yielding a detection limit of 0.2 ng/ml. This sensitivity is comparable with the best results obtained by atomic emission flame spectrometry.

Experimental Study on Testing Ni-Containing Stainless Steel Protective Coatings by Pulsed Laser Scratching

2010 ◽  
Vol 43 ◽  
pp. 651-656
Author(s):  
Ai Xin Feng ◽  
Yu Peng Cao ◽  
Chuan Chao Xu ◽  
Huai Yang Sun ◽  
Gui Fen Ni ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Power Density ◽  
Laser Power ◽  
Protective Coatings ◽  
Three Dimensional ◽  
Pulsed Laser ◽  
Laser Power Density ◽  
The Matrix ◽  
The Impact

In the experiment, we use pulsed laser to conduct discrete scratching on Ni-containing stainless steel protective coatings to test residual stress situation after the matrix is scratched; then to analyze the the impact of the impact stress wave on coating - substrate bonding strength according to the test results, finally to infer the laser power density range within which it occurs coating failure. The study shows that: after laser discrete scratching, the residual stress of the center of the laser-loaded point on matrix surface gradually reduces when the pulsed laser power density increases. The matrix produces a corresponding residual compressive stress under the laser power density reaches a certain value. The actual failure threshold values are 12.006 GW/cm2, 11.829GW/cm2 and 12.193GW/cm2 measured by the three-dimensional topography instrument testing the discrete scratch point of three groups of samples and verified by using a microscope

Numerical Simulation and Applications of a Method for Attenuating Laser Power Density

2013 ◽  
Vol 50 (2) ◽  
pp. 022201
Author(s):  
王振宝 Wang Zhenbao ◽  
冯国斌 Feng Guobin ◽  
杨鹏翎 Yang Pengling ◽  
冯刚 Feng Gang ◽  
闫燕 Yan Yan
Keyword(s):  
Numerical Simulation ◽  
Power Density ◽  
Laser Power ◽  
Laser Power Density

scholarly journals Investigation on Residual Stress Loss during Laser Peen Texturing of 316L Stainless Steel

2019 ◽  
Vol 9 (17) ◽  
pp. 3511 ◽  
Author(s):  
Kangmei Li ◽  
Yifei Wang ◽  
Yu Cai ◽  
Jun Hu
Keyword(s):  
Residual Stress ◽  
Compressive Stress ◽  
Power Density ◽  
Laser Power ◽  
Surface Deformation ◽  
Laser Power Density ◽  
Residual Compressive Stress ◽  
Laser Spot ◽  
Residual Tensile Stress ◽  
Spot Radius

Laser peen texturing (LPT) is a novelty way of surface texturing based on laser shock processing. One of the most important benefits of LPT is that it can not only fabricate surface textures but also induce residual compressive stress for the target material. However, the residual stress loss leads to partial loss of residual compressive stress and even causes residual tensile stress at the laser spot center. This phenomenon is not conducive to improving the mechanical properties of materials. In this study, a numerical simulation model of LPT was developed and validated by comparison of surface deformation with experiments. In order to investigate the phenomenon of residual stress loss quantitatively, an evaluation method of residual stress field was proposed. The effects of laser power density and laser spot radius on the residual stress, especially the residual stress loss, were systematically investigated. It is found that with the increase of laser power density or laser spot radius, the thickness of residual compressive layer in depth direction becomes larger. However, both the magnitude and the affecting zone size of residual stress loss will be increased, which implies a more severe residual stress loss phenomenon.

Tuning the Defects in AgO Nanoparticles/Graphene Bilayers System by Laser Power Density

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
H. Ferreira ◽  
M. Briones2, M. Camilo ◽  
G. Poma ◽  
Maria Quintana ◽  
A. Champi
Keyword(s):  
Power Density ◽  
Laser Power ◽  
Laser Power Density

Characterizing the Effect of Laser Power Density on Microstructure, Microhardness, and Surface Finish of Laser Deposited Titanium Alloy

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Rasheedat M. Mahamood ◽  
Esther T. Akinlabi ◽  
Mukul Shukla ◽  
Sisa Pityana
Keyword(s):  
Surface Roughness ◽  
Titanium Alloy ◽  
Power Density ◽  
Surface Finish ◽  
Laser Power ◽  
Optical Microscope ◽  
Laser Power Density ◽  
Grain Structure ◽  
Selection Of

This paper reports the effect of laser power density on the evolving properties of laser metal deposited titanium alloy. A total of sixteen experiments were performed, and the microstructure, microhardness and surface roughness of the samples were studied using the optical microscope (OP), microhardness indenter and stylus surface analyzer, respectively. The microstructure changed from finer martensitic alpha grain to coarser Widmastätten alpha grain structure as the laser power density was increased. The results show that the higher the laser power density employed, the smoother the obtained surface. The microhardness initially increased as the laser power density was increased and then decreased as the power density was further increased. The result obtained in this study is important for the selection of proper laser power density for the desired microstructure, microhardness and surface finish of part made from Ti6Al4V.

Preparation and Microstructure Control of Protein Thin Films Deposited by Pulsed Laser Deposition and Via Colloid Chemical Routes

2003 ◽  
Vol 788 ◽  
Author(s):  
Sayuri Nakayama ◽  
Ichiro Taketani ◽  
Sanshiro Nagare ◽  
Mamoru Senna
Keyword(s):  
Thin Film ◽  
Secondary Structure ◽  
Pulsed Laser Deposition ◽  
Power Density ◽  
Laser Power ◽  
Pulsed Laser ◽  
Laser Power Density ◽  
Laser Deposition ◽  
Random Coil ◽  
Β Sheet

ABSTRACTProtein thin film (mainly silk fibroin) was prepared by pulsed laser deposition (PLD) with 1064nm IR-beam and via colloid chemical routes. Thickness, surface roughness, and microstructures of the deposited film were examined by quartz crystal microbalance sensor, field emission scanning electron microscope (FE-SEM), and atomic force microscope (AFM). The laser power density was varied systematically for PLD to control the microstructures of the film and the secondary structure (β-sheet, α-helix, or random coil) of the protein. Secondary structure of the target and film was examined by FT-IR. Films prepared by PLD comprise by agglomerated particles with their primary particle size around 30nm. The size of the primary particles was uniform, especially for the film prepared at low laser power density. At low laser power density, proportion of β-sheet increased and that of random coil decreased. Proportion of random coil was also increased by the wet colloidal process. PLD with low power density is most suitable to preserve the secondary structure in the protein thin film.

Sign in / Sign up

Export Citation Format

Share Document