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.

scholarly journals Effect of Laser Shock Peening on Fretting Fatigue Life of TC11 Titanium Alloy

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4711
Author(s):  
Xufeng Yang ◽  
Hongjian Zhang ◽  
Haitao Cui ◽  
Changlong Wen
Keyword(s):  
Titanium Alloy ◽  
Fatigue Life ◽  
Power Density ◽  
Laser Power ◽  
Fretting Fatigue ◽  
Laser Power Density ◽  
Laser Shock Peening ◽  
Laser Shock ◽  
Shock Peening ◽  
Tc11 Titanium Alloy

The purpose of this paper is to investigate the performance of laser shock peening (LSP) subjected to fretting fatigue with TC11 titanium alloy specimens and pads. Three laser power densities (3.2 GW/cm2, 4.8 GW/cm2 and 6.4 GW/cm2) of LSP were chosen and tested using manufactured fretting fatigue apparatus. The experimental results show that the LSP surface treatment significantly improves the fretting fatigue lives of the fretting specimens, and the fretting fatigue life increases most when the laser power density is 4.8 GW/cm2. It is also found that with the increase of the laser power density, the fatigue crack initiation location tends to move from the surface to the interior of the specimen.

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.

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

Grain Structure and Surface Roughness of Four Commercial NiTi Orthodontic Archwires

2017 ◽  
Vol 266 ◽  
pp. 257-263
Author(s):  
Wassana Wichai ◽  
Rutchadakorn Isarapatanapong ◽  
Niwat Anuwongnukroh ◽  
Surachai Dechkunakorn
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Optical Microscope ◽  
Grain Structure ◽  
Wire Surface ◽  
Average Grain Size ◽  
Electron Mode ◽  
The Mean ◽  
The Wire ◽  
Orthodontic Archwires

This study investigated four commercially available NiTi orthodontic archwires from different manufactures for their grain structure and surface roughness.Four commercially available pre-formed NiTi orthodontic archwire (Ormco, Sentalloy, Highland and NIC) with diameter 0.016 x 0.022 inch2 were tested. The wire samples were polished and etched to evaluate the morphology and structure of wire surface. Each NiTi archwire was investigated under a reflected light microscope of an Optical Microscope to analyze its grain structure and size, in longitudinal surfaces. The surfaces of wire were qualitatively examined in the secondary electron mode at common magnification (500X). The surface roughness was also evaluated by a surface roughness tester. The descriptive statistic was evaluated the mean and standard deviation of surface roughness and Medcale T-Test was to test the mean difference of the surface roughness in each brands. This study showed an average grain size of 2-8 μm for each NiTi archwire. The wire surface of Ormco and Highland showed straiations along the longitudinal axes, however Sentalloy and NIC showed small pores on the wire surface. The surface roughness was 0.09 μm for Highland, 0.25 μm for Sentalloy, 0.28 μm for Ormco and 0.46 μm for NIC archwire. The Highland was smoothest and NIC was the roughest. There were in significant (p < 0.05) difference of surface roughness of each brands. The results showed that the four manufactures NiTi archwires were different in grain size, wire surface and surface roughness. During clinical application, these archwires may exhibit different mechanical properties, such as strength, hardness, ductity, and friction because of their microstructure.

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

Effects of Flap Wheel Grinding Parameters on Surface Roughness for Stainless Steel

2014 ◽  
Vol 548-549 ◽  
pp. 506-509 ◽  
Author(s):  
Jirayu Somgumnerd ◽  
Viboon Tangwarodomnukun ◽  
Suksan Prombanpong
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Surface Finish ◽  
Operating Conditions ◽  
Success Factor ◽  
Polishing Process ◽  
Fine Surface ◽  
Key Success Factor ◽  
Selection Of

The polishing process plays an important role in the stainless steel cookware since an appearance is one of the prime quality criterions of the product. Typically, there are three sequential steps in the polishing process using abrasive flap wheel, sisal and cloth respectively. The abrasive flap wheel is the first step in the process which aims to rapidly create fine surface finish on the product. Thus, the selection of appropriate flap wheel as well as operating conditions in order to achieve surface finish within the required cycle time i.e. 12 seconds are the key success factor. Therefore, the experimental design is conducted and analyzed. It is found that there are four factors which influence the surface roughness: grits size of flap wheel, polishing time, velocity, and force. It can also be concluded from the analysis that the roughness is directly proportional to grit size and force but it is inversely proportional to velocity. In addition, the optimal condition for the case study can also be obtained.

Machining Finish of Titanium Alloy Prepared by Additive Manufacturing

2017 ◽  
Vol 872 ◽  
pp. 43-48 ◽  
Author(s):  
Xin Huang ◽  
Qian Bai ◽  
Yong Tao Li ◽  
Bi Zhang
Keyword(s):  
Surface Roughness ◽  
Titanium Alloy ◽  
Additive Manufacturing ◽  
Surface Finish ◽  
Functional Performance ◽  
Critical Role ◽  
Lower Surface ◽  
Machining Parameters ◽  
Machined Surface ◽  
Slot Milling

Surface finish plays a critical role in functional performance of machined components. This study investigates machining finish of Ti-6Al-4V alloy prepared by Additive Manufacturing (AM) with a series of slot-milling experiments. The study compares the machined AMed part with that made of the conventional wrought Ti-6Al-4V. The microstructure of AMed parts is acicular α and Widmanstatten α lath structures compared to lamellar α structure of that in the wrought parts. Due to the unique microstructure from AM process, the AMed parts present higher strength and lower ductility. Therefore, a lower surface roughness is obtained in the milling of AMed parts compared to its counterpart of wrought parts. In addition, the machined surface of AMed parts possesses a topography of discontinued ridges. It is believed that the topography is due to low ductility of AMed part. The results show that the machined AMed part presents better surface finish. The study provides a guidance to optimization of machining parameters for AMed Ti-6Al-4V alloys.

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