scholarly journals Nd:YVO4 Laser Irradiation on Cr3C2-25(Ni20Cr) Coating Realized with High Velocity Oxy-Fuel Technology—Analysis of Surface Modification

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1477
Author(s):  
Luca Giorleo ◽  
Giovina Marina La Vecchia ◽  
Elisabetta Ceretti
Keyword(s):  
Surface Modification ◽  
High Velocity ◽  
Laser Scanning ◽  
High Hardness ◽  
Hard Metal ◽  
Machining Process ◽  
Laser Source ◽  
Thermal Source ◽  
Powder Particles ◽  
Mechanical Machining

The high-velocity oxy-fuel (HVOF) technique has been extensively used for the deposition of hard metal coatings. The main advantage of HVOF, compared to other thermal spray techniques, is its ability to accelerate the melted powder particles of the feedstock material to a relatively high velocity, leading to good adhesion and low porosity. To further improve the surface properties, a mechanical machining process is often needed; however, a key problem is that the high hardness of the coating makes the polishing process expensive (in terms of time and tool wear). Another approach to achieving surface modification is through interaction with a thermal source, such as a laser beam. In this research, the effects of laser scanning rate, scanning strategy, and number of loop cycles were investigated on an HVOF-coated surface. Cr3C2-25(Ni20Cr) was selected as the coating and Nd:YVO4 as the laser source. The results demonstrate the significance of the starting coating morphology and how the laser process parameters can be tuned to generate different types of modifications, ranging from polishing to texturing.

scholarly journals Understanding the Influence of High Velocity Thermal Spray Techniques on the Properties of Different Anti-Wear WC-Based Coatings

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1157
Author(s):  
Andrea Garfias Bulnes ◽  
Vicente Albaladejo Fuentes ◽  
Irene Garcia Cano ◽  
Sergi Dosta
Keyword(s):  
Grain Size ◽  
Corrosion Resistance ◽  
Abrasive Wear ◽  
Thermal Spray ◽  
High Velocity ◽  
Metallic Matrix ◽  
High Hardness ◽  
Hard Metal ◽  
Characterization Methods ◽  
X Ray

This work analyzes the differences found in hard metal coatings produced by two high velocity thermal spray techniques, namely high velocity oxy-fuel (HVOF) and high velocity air-fuel (HVAF). Additionally, the effect of the metallic matrix and ceramic composition and the original carbide grain size on coating properties is compared to the most studied standard reference material sprayed by HVOF, WC-Co. For this evaluation, the physical properties of the coatings, including feedstock characteristics, porosity, thickness, roughness, hardness, and phase composition were investigated. Several characterization methods were used for this purpose: optical microscopy (OM), scanning electronic microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and X-ray Diffraction (XRD), among others. The final performance (abrasive wear and corrosion resistance) shown by the coatings obtained by these two methodologies was also analyzed. Thus, the abrasive wear resistance was analyzed by the rubber-wheel test, while the corrosion resistance was characterized with electrochemical methods. The characterization results obtained clearly showed that the coatings exhibit different microstructures according to feedstock powder characteristics (carbide grain size and/or composition) and the thermal spray process used for its deposition. Thus, the incorporation of WB to the cermet composition led to a high hardness coating, and the complementary hardness and toughness of the WC-Co coatings justify its better abrasion resistance. The presence of Ni on the metal matrix increases the free corrosion potential of the coating to more noble region. However, the WC-Co coatings show a lower corrosion rate and hence a higher protective performance than the rest of the coatings.

scholarly journals Wear in hard metal check valves: In-situ surface modification through tribolayer formation in dry contact

Vacuum ◽  
2021 ◽  
pp. 110482
Author(s):  
A. Blutmager ◽  
M. Varga ◽  
U. Cihak-Bayr ◽  
W. Friesenbichler ◽  
P.H. Mayrhofer
Keyword(s):  
Surface Modification ◽  
Hard Metal ◽  
Dry Contact

Kinetics of high-velocity penetration into high-hardness brittle media

1999 ◽  
Vol 41 (10) ◽  
pp. 1638-1640 ◽  
Author(s):  
A. S. Vlasov ◽  
Yu. A. Emel’yanov ◽  
E. L. Zil’berbrand ◽  
A. A. Kozhushko ◽  
A. I. Kozachuk ◽  
...  
Keyword(s):  
High Velocity ◽  
High Hardness ◽  
Kinetics Of

Dissolution Behavior of Cast WC Particles in NiCrBSi-WC Coatings by Laser Induction Hybrid Cladding

2013 ◽  
Vol 668 ◽  
pp. 283-287
Author(s):  
Sheng Feng Zhou ◽  
Xiao Qin Dai
Keyword(s):  
High Speed ◽  
Laser Scanning ◽  
Metallic Matrix ◽  
High Hardness ◽  
Scanning Speed ◽  
Eutectic Structure ◽  
Dissolution Behavior ◽  
Positive Role ◽  
Laser Scanning Speed ◽  
Laser Induction

In order to characterize the dissolution of cast WC particles in Ni-based WC coatings by laser induction hybrid rapid cladding, NiCrBSi+50 wt.% WC coatings are produced on A3 steel by low and high speed laser induction hybrid cladding (LIHC). When laser scanning speed is only 600 mm/min, the crack-free coating has pores and its dilution is as high as 45%. At the bottom of coating, the cast WC particles are dissolved completely and the herringbone M6C eutectics are precipitated. In the center of coating, the cast WC particles are also dissolved completely and the acicular, blocky and dendritic carbides with relatively low hardness are precipitated. At two sides of coating, some cast WC particles are dissolved partially and interact with Ni-based alloy to form an alloyed reaction layer, while others preserve the primary eutectic structure and high hardness. When laser scanning speed and powder feeding rate are increased to 1500 mm/min and 85.6 g/min, the coating has cracks but no pores. Its dilution can be markedly decreased to 7.8%. Moreover, a majority of WC particles are still composed of primary eutectic structure and keep their high hardness, which can play a positive role in strengthening Ni-based metallic matrix.

scholarly journals Investigation to Improve the Pool Boiling Heat Transfer Characteristics Using Laser-Textured Copper-Grooved Surfaces

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Dharmendra Mani ◽  
Suresh Sivan ◽  
Hafiz Muhammad Ali ◽  
Udaya Kumar Ganesan
Keyword(s):  
Heat Transfer ◽  
Surface Modification ◽  
Pool Boiling ◽  
Research Work ◽  
Picosecond Laser ◽  
Machining Process ◽  
Laser Machining ◽  
Textured Surface ◽  
Surface Characterisation ◽  
Different Depths

Improving the performance of pool boiling with critical heat flux of pool boiling and enhancing the coefficient of heat transfer through surface modification technique have gained a lot of attention. These surface modifications can be done at different scales using various techniques. However, along with the performance improvement, the durability and stability of the surface modification are very crucial. Laser machining is an attractive option in this aspect and is gaining a lot of attention. In the present experimentation research work, pool boiling attributed performance of copper-grooved surfaces obtained through picosecond laser machining method is investigated. The performance of the modified surfaces was compared with the plain surface serving as reference. In this, three square grooved patterns with the same pitch (100 μm) and width (100 μm) but different depths (30, 70, and 100 μm) were investigated. Different depths were obtained by varying the scanning speed of the laser machine. In addition to the microchannel effect, the grain structuring during the laser machining process creates additional nucleation sites which has proven its effectiveness in improving the pool boiling performance. In all aspects, the pool boiling performance of the grooved laser-textured surface has showed increased surface characterisation as compared with the surface of copper.

Surface Modification and Ablation of Insulators Using a Tunable, Picosecond Mid-Infrared Laser

1998 ◽  
Vol 526 ◽  
Author(s):  
R. F. Haglund ◽  
D. R. Ermer ◽  
A. H. Lines ◽  
M. R. Papantonakis ◽  
H. K. Park ◽  
...  
Keyword(s):  
Surface Modification ◽  
Near Infrared ◽  
Energy Content ◽  
Laser Energy ◽  
Vibrational Excitation ◽  
Average Power ◽  
Surface Modifications ◽  
Fused Silica ◽  
Laser Source ◽  
Near Ultraviolet

AbstractUltrashort-pulse lasers with fundamental wavelengths ranging from near-infrared to near-ultraviolet are increasingly being used for laser-induced surface modification of non-metallic solids. The relaxation of the initial electronic excitation into vibrational relaxation modes can produce efficient ablation and other desirable surface modifications with little collateral damage because the laser energy is deposited on a time scale much shorter than thermal diffusion times. Little is known, however, about how ultrashort pulses interact with insulators at wavelengths in the vibrational infrared. This paper describes surface modifications achieved by picosecond laser irradiation in the 2-10 lim range. The laser source was a tunable, free-electron laser (FEL) with I-ps micro-pulses spaced 350 ps apart in a macropulse lasting up to 4 μs, with an average power of up to 3 W. This unusual pulse structure makes possible novel tests of the influences vs fluence and intensity, as well as the effects of resonant vibrational excitation. As model materials systems, we studied calcium carbonate, its isoelectronic cousin sodium nitrate, and fused silica. Particularly intriguing are surface modifications achieved by tuning the laser into vibrational resonances and overtones of the target materials, or by tailoring the energy content of the pulse. The mechanisms underlying these effects, and their implications for materials-modification strategies, are discussed.

Material perspective on the evolution of micro- and nano-scale cutting of metal alloys

2018 ◽  
Vol 1 (2) ◽  
pp. 97-114 ◽  
Author(s):  
M. Azizur Rahman ◽  
Mustafizur Rahman ◽  
A. Senthil Kumar
Keyword(s):  
Active Role ◽  
Machining Process ◽  
Metal Alloys ◽  
Sensors And Actuators ◽  
Nano Scale ◽  
Subtractive Manufacturing ◽  
Manufacturing Technologies ◽  
Mechanical Sensors ◽  
Metallic Parts ◽  
Mechanical Machining

Microfabrication plays an active role in miniaturization of products and components in various emerging fields ranging from pharmaceuticals and bio-medical applications to electro-mechanical sensors and actuators to chemical microreactors and mechanical microturbines. Tool-based machining is one of the key technologies of microfabrication. The machining of materials on the micrometre and nanometre scales is fundamental for the fabrication of 3D micro components. However, there are limitations of scaling down the mechanical machining process from the macro- to micro- to nanoscales. Several factors that are not significant in conventional machining become significant in micro/nano-scale machining. This article identifies the important material-related issues on the evolution of micro cutting from conventional cutting process. The main focus is given to the state-of-the art micro/nano-cutting technologies of metal alloys with material perspective. Furthermore, a promising research of coupling the additive and subtractive manufacturing technologies has been highlighted to improve the surface quality of 3D-printed metallic parts.

Experimental Study of Machining of Smart Materials Using Submerged Abrasive Waterjet Micromachining Process

2018 ◽  
Author(s):  
Sagil James ◽  
Anurag Mahajan
Keyword(s):  
Experimental Study ◽  
Smart Materials ◽  
Thermal Stresses ◽  
Piezoelectric Materials ◽  
High Hardness ◽  
Machining Process ◽  
Critical Parameters ◽  
Abrasive Waterjet ◽  
Parameter Study ◽  
Wide Range

Smart materials are new generation materials which possess great properties to mend themselves with a change in environment. Smart materials find applications in a wide range of industries including biomedical, aerospace, defense and energy sector and so on. These materials possess unique properties including high hardness, high strength, high melting point and low creep behavior. Manufacturing of these materials is a huge challenge, particularly at the micron scale. Abrasive waterjet micromachining (AWJMM) is a non-traditional material removal process which has the capability of machining extremely hard and brittle materials such as glasses and ceramics. AWJMM process is usually performed with nozzle and workpiece placed in air. However, machining in the air causes spreading of the waterjet resulting in low machining quality. Performing the AWJMM process with a submerged nozzle and workpiece could eliminate this problem and also reduce noise, splash, and airborne debris particles during the machining process. This research investigates Submerged Abrasive Waterjet Machining (SAWJMM) process for micromachining smart ceramic materials. The research involves experimental study on micromachining of smart materials using an in-house fabricated SAWJMM setup. The effect of critical parameters including stand-off distance, abrasive grain size and material properties on the cavity size, kerf angle and MRR during SAWJMM and AWJMM processes are studied. The study found that SAWJMM process is capable of successfully machining smart materials including shape memory alloys and piezoelectric materials at the micron scale. The machined surfaced are free of thermal stresses and did not show any cracking around the edges. The critical process parameter study revealed that stand-off distance and abrasive grit size significantly affect the machining results.

Experimental Study of Micromachining on Borosilicate Glass Using CO2 Laser

2020 ◽  
Vol 143 (5) ◽  
Author(s):  
Vishnu Vardhan Posa ◽  
Murali Sundaram
Keyword(s):  
Laser Scanning ◽  
Laser Energy ◽  
Removal Rate ◽  
Scanning Speed ◽  
Machining Process ◽  
Laser Machining ◽  
Glass Work ◽  
Workpiece Material ◽  
Laser Parameters ◽  
Wide Range

Abstract Laser beam machining (LBM) is a versatile process that can shape a wide range of engineering materials such as metals, ceramics, polymers, and composite materials. However, machining of glass materials by LBM is a challenge as most of the laser energy is not absorbed by the surface. In this study, an attempt has been made to increase the absorptivity of the glass material by using a coating on the surface of the material. Glass has been used in this study because of its extensive applications in the micro-opto-electro-mechanical systems. The optimal machining depends on both laser parameters and properties of the workpiece material. There are number of laser parameters that can be varied in the laser machining process. It is difficult to find optimal laser parameters due to the mutual interaction of laser parameters. A statistical study based on design of experiment (DoE) has been made to study the effect of coating and parameters like laser power, laser scanning speed, angle of inclination of the workpiece on depth of the slot, width of the slot, aspect ratio, and material removal rate (MRR) in the laser machining process using 2k factorial design and analysis of variance (ANOVA). On an average, four times increase in depth of the slot, two times increase in width of the slot and seven times increase in the MRR were observed in the glass samples with coating when compared to uncoated glass work samples.

Surface integrity in laser-assisted machining of Ti6Al4V

2020 ◽  
pp. 095440622097825
Author(s):  
O Kalantari ◽  
MM Fallah ◽  
F Jafarian ◽  
SR Hamzeloo
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Surface Integrity ◽  
Cutting Tool ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Laser Source ◽  
Depth Of Cut ◽  
Thermal Source ◽  
Laser Assisted Machining

In laser-assisted machining (LAM), the laser source is focused on the workpiece as a thermal source and locally increases the workpiece temperature and makes the material soft ahead of the cutting tool so using this method, the machining forces are reduced, which causes improving the surface quality and cutting tool life. Machinability of advanced hard materials is significantly low and conventional methods do not work effectively. Therefore, utilizing an advanced method is inevitable. The product life and performance of complex parts of the leading industry depends on surface integrity. In this work, the surface integrity features including microhardness, grain size and surface roughness (Ra) and also the maximum cutting temperature were investigated experimentally in LAM of Ti-6Al-4V. According to the results, cutting speed has inverse effect on the effectiveness of LAM process because with increasing speed (15 to 63 m/min), temperature decreases (524 °C to 359 °C) and surface roughness increases (0.57 to 0.71 μm). Enhancing depth of cut and feed has direct effect on the process temperature, grain size, microhardness and surface roughness.

Sign in / Sign up

Export Citation Format

Share Document