scholarly journals Peculiarities of laser cladding with feeding of the filler tape

2018 ◽  
pp. 95-100
Author(s):  
A. P. Yelistratov
Keyword(s):  
Energy Density ◽  
Laser Beam ◽  
Surface Treatment ◽  
Laser Energy ◽  
Metal Strip ◽  
Efficient Tool ◽  
Surface Strengthening ◽  
Wide Range ◽  
Metal Layers ◽  
Metallurgical Processes

Semiconductor laser has some features that make it an efficient tool for surface treatment of metals, in particular for surface strengthening. It provides high enough concentration of energy in the heat spot, possibility to adjust process parameters in wide range. Insignificant, compare to other types of laser, energy density eliminates an extensive penetration and internal melting of the metal, which is very important for surface treatment and for the wear resistant covering.Method of metal layers deposition by feeding a metal strip and its melting by laser beam was developed. Metallurgical processes of the deposit lay forming were investigated; method of feeding the filler strip was optimized.

Effect of Temperature on the Evolved Microstructure During Laser Beam Forming of Sheet Steels

2017 ◽  
Author(s):  
Stephen Akinlabi ◽  
Madindwa Mashinini ◽  
Esther Akinlabi
Keyword(s):  
High Temperature ◽  
Energy Density ◽  
Laser Beam ◽  
Laser Energy ◽  
High Energy ◽  
Phase Changes ◽  
High Energy Density ◽  
Effect Of Temperature ◽  
Beam Forming ◽  
Heating And Cooling

Laser Beam Forming (LBF) being a novel technique and non-contact manufacturing process, employs laser beam as the tool of shaping and bending metal sheets into different shapes and curvatures for various applications. LBF is a high-temperature process, where rapid heating and cooling occurs causing microstructural changes like dynamic recrystallization and phase changes. The study becomes necessary to ensure that the structural integrity of the processed material is not compromised. Hence, the investigation focuses on the effect of temperature on the developed microstructure during the LBF process. The design of experiment was considered, using three levels and five factors. The experimentally measured curvatures were validated with the predicted measured curvatures, which were found to be in agreement. The result shows that the developed ferrite and pearlite grains were due to the heating and cooling. Furthermore, the average grain sizes at a low energy density of about 355°C and high energy density of about 747°C were found to be about 10 μm and 6 μm respectively. It is implied that the high temperature from the high laser energy aided the deformation of the grains significantly. However, such high temperature must be closely monitored so to avoid metallurgical notches in the processed component.

scholarly journals Experimental investigations for a postweld heat treatment on Ti-6Al-4V titanium welds with a defocused laser beam

2020 ◽  
Vol 321 ◽  
pp. 11034
Author(s):  
J.D. Beguin ◽  
Y. Balcaen ◽  
J. Alexis ◽  
E. Andrieu
Keyword(s):  
Heat Treatment ◽  
Energy Density ◽  
Laser Beam ◽  
Local Heating ◽  
Minimum Energy ◽  
Pure Titanium ◽  
Postweld Heat Treatment ◽  
Experimental Investigations ◽  
Commercially Pure Titanium ◽  
Wide Range

The purpose of this study is to apply a local heat treatment (LHT), in-situ, on the weld bead, using a defocused Yb: YAG laser beam on a continuous regime, in order to reduce residual stresses and decompose the brittle a’ martensite, into a lamellae and fine β phase. Laser scan experiments were firstly performed on a commercially pure titanium grade 2, with a wide range of parameters, in order to provide a “heat treatment window” without titanium melting. After optimization of the processing parameters, to obtain a sufficient width and depth for the scanning zone, experiments have been performed on a β-treated, fully martensitic Ti-6Al-4V sheet. For each processing experiments, the decomposition of a’, was studied based on metallographic cross sections. A local heating with a minimum energy density at 700 J.cm-2, has a sufficient effect to destabilize a’, while for an energy density at 1000 J.cm-2 , a diffusional transformation take place, with the formation of Widmanstätten microstructure. Finally, these optimized conditions were applied on a full penetration Ti-6Al-4V welds. The results of the LHT will be described in terms of the microstructural changes observed in the welded zone and hardness evolution.

Excimer Laser Induced Crystallization of Amorphous Silicon Near Threshold

1989 ◽  
Vol 157 ◽  
Author(s):  
R.Z. Bachrach ◽  
K. Winer ◽  
J.B. Boyce ◽  
F.A. Ponce ◽  
S.E. Ready ◽  
...  
Keyword(s):  
Energy Density ◽  
Laser Beam ◽  
Amorphous Silicon ◽  
Excimer Laser ◽  
Laser Energy ◽  
Laser Energy Density ◽  
Square Root ◽  
Threshold Behavior ◽  
Sharp Threshold ◽  
Induced Crystallization

ABSTRACTUsing a suitably homogenized excimer laser beam, we have shown that the threshold for crystallization of amorphous silicon is well defined and exhibits a square root dependence on the laser energy density above threshold. This sharp threshold behavior can be exploited in a number of ways.

Pulsed Laser Etching of GaN and AIN Films

1997 ◽  
Vol 482 ◽  
Author(s):  
H. Chen ◽  
R. D. Vispute ◽  
V. Talyansky ◽  
R. Enck ◽  
S. B. Ogale ◽  
...  
Keyword(s):  
Energy Density ◽  
Laser Energy ◽  
Etching Rate ◽  
Pulsed Laser ◽  
Dry Etching ◽  
Laser Energy Density ◽  
Etch Depth ◽  
Layer By Layer ◽  
Laser Etching ◽  
Wide Range

AbstractDue to limited success in wet etching of GaN and AIN, dry etching techniques have become more relevant for the processing of the GaN films. Here we demonstrate the results of an alternative dry etching process, namely, pulsed laser etching, for GaN and AIN. In this method, a KrF pulsed excimer laser (λ=248 nm, τ=30 ns) was used to etch epitaxial GaN and AIN films. The dependence of the etching characteristics on the laser energy density and the number of pulses has been studied. The etch depth showed a linear dependence on the number of pulses over a wide range of laser energy densities. The threshold intensity for GaN etching was determined to be 0.33 J/cm2. The etching rate was found to be a strong function of laser energy density. Above the threshold, the etch rate was found to be 300–1400 Å per pulse leading to etching rates of 0.1–1μm/sec depending upon the laser energy density and the pulse repetition rate. It is shown that the etching mechanism is based on laser induced absorption, decomposition and layer by layer removal of the GaN.

Effect of preliminary laser surface treatment on mechanical properties of diffusion welded joints of Fe-Ni alloy

2020 ◽  
pp. 40-47
Author(s):  
V.N. Yolkin ◽  
◽  
T.V. Malinsky ◽  
Yu.V. Khomich ◽  
V.A. Yamshchikov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Density ◽  
Surface Treatment ◽  
Laser Treatment ◽  
Ultimate Strength ◽  
Weld Joint ◽  
Laser Energy ◽  
Laser Energy Density ◽  
Weld Joints ◽  
Ni Alloy

The experimental studies of the effect of preliminary laser pulsed surface treatment on mechanical properties of the diffusion welding joints of Fe-Ni alloy were carried out. The alloy surfaces was treated in inert gas (Ar) environment by scanning beam of nanosecond laser pulses with a wavelength 355 nm, repetition rate 100 Hz and scanning speed 1 mm/s. Laser spot was 220 µm, the energy density 2 and 3 J/cm2. Treated samples as well as the control untreated ones were placed at the same container and were diffusion bonded by hot isostatic pressing (HIP) at the temperatures of 1000 and 1160°С. Ultimate strength and elongation of weld joint materials were determined by tensile testing. It is shown that laser pulse treatment leads to improvement both the ultimate strength and relative elongation of the weld joints. Mechanical properties of the weld joints depends on the laser energy density. Weld joint properties can be increased by optimization of the laser treatment parameters. The best results were achieved at laser energy density 2 J/cm2. Ultimate strength was increased by 12% and 29% for HIP temperatures 1160 and 1000°С respectively. The elongation values also increased from 42% for non-treated samples up to 51% for samples treated at 2 J/cm2 energy density. Preliminary laser treatment of welded surfaces permits to reduce the HIP temperature by 160°С and thereby reduce power consumption during HIP process.

scholarly journals Unified Model for Laser Doping of Silicon from Precursors

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2322
Author(s):  
Mohamed Hassan ◽  
Morris Dahlinger ◽  
Jürgen R. Köhler ◽  
Renate Zapf-Gottwick ◽  
Jürgen H. Werner
Keyword(s):  
Laser Pulse ◽  
Laser Beam ◽  
Laser Energy ◽  
Unified Model ◽  
Wafer Surface ◽  
Surface Tension Gradient ◽  
Molten Silicon ◽  
Laser Doping ◽  
Wide Range ◽  
Doping Profiles

Laser doping of silicon with the help of precursors is well established in photovoltaics. Upon illumination with the constant or pulsed laser beam, the silicon melts and doping atoms from the doping precursor diffuse into the melted silicon. With the proper laser parameters, after resolidification, the silicon is doped without any lattice defects. Depending on laser energy and on the kind of precursor, the precursor either melts or evaporates during the laser process. For high enough laser energies, even parts of the silicon’s surface evaporate. Here, we present a unified model and simulation program, which considers all these cases. We exemplify our model with experiments and simulations of laser doping from a boron oxide precursor layer. In contrast to previous models, we are able to predict not only the width and depth of the patterns on the deformed silicon surface but also the doping profiles over a wide range of laser energies. In addition, we also show that the diffusion of the boron atoms in the molten Si is boosted by a thermally induced convection in the silicon melt: the Gaussian intensity distribution of the laser beam increases the temperature-gradient-induced surface tension gradient, causing the molten Si to circulate by Marangoni convection. Laser pulse energy densities above H > 2.8 J/cm2 lead not only to evaporation of the precursor, but also to a partial evaporation of the molten silicon. Without considering the evaporation of Si, it is not possible to correctly predict the doping profiles for high laser energies. About 50% of the evaporated materials recondense and resolidify on the wafer surface. The recondensed material from each laser pulse forms a dopant source for the subsequent laser pulses.

CENTRI-CAST GRAY IRON 55

Alloy Digest ◽  
1979 ◽  
Vol 28 (9) ◽  
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Physical Properties ◽  
Surface Treatment ◽  
Heat Treating ◽  
Gray Iron ◽  
Centrifugally Cast ◽  
Wide Range ◽  
Nominal Tensile Strength ◽  
Cast Gray Iron

Abstract CENTRI-CAST GRAY IRON 55 is a centrifugally cast gray iron with a nominal tensile strength of 55,000 psi. It is produced in the form of tubing which has a wide range of uses in applications where size and shape are of paramount importance and freedom from pattern cost is an important consideration. Typical applications are seals, bushings, farm machinery, casings and general machinery uses. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, tensile properties, and compressive and shear strength as well as fatigue. It also includes information on casting, heat treating, machining, and surface treatment. Filing Code: CI-48. Producer or source: Federal Bronze Products Inc..

CHASE 14310

Alloy Digest ◽  
1977 ◽  
Vol 26 (10) ◽  
Keyword(s):  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Heat Treating ◽  
Thermal Softening ◽  
High Conductivity ◽  
Wide Range

Abstract CHASE 14310 is a high-conductivity copper with excellent resistance to thermal softening. It is a deoxidized, electronic grade of copper with excellent formability, weldability and plateability. It is available in strip form and has a wide range of applications. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: Cu-341. Producer or source: Chase Brass & Copper Company Inc..

SAE 1345

Alloy Digest ◽  
1987 ◽  
Vol 36 (5) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Alloy Steel ◽  
Heat Treating ◽  
Hand Tools ◽  
Manganese Alloy ◽  
Steel Mills ◽  
Wide Range

Abstract SAE 1345 is a through-hardening, manganese alloy steel with intermediate hardenability. It is most commonly used where good strength is needed but low-to-medium toughness is sufficient. Its wide range of uses in tools and machinery includes hand tools, gears, shafts, bolts and housings. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-425. Producer or source: Alloy steel mills and foundries.

SAE 8642

Alloy Digest ◽  
1981 ◽  
Vol 30 (7) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
Alloy Steel ◽  
High Strength ◽  
Heat Treating ◽  
Steel Mills ◽  
Wide Range ◽  
Strength And Toughness

Abstract SAE 8642 is a triple-alloy steel that can be hardened by austenitizing and quenching in oil. This steel has moderate hardenability with relative high strength and toughness, especially in the quenched-and-tempered condition. It is used in a wide range of components, parts and tools; examples are bolts, shafts, gears, wrenches, axles and housings. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-382. Producer or source: Alloy steel mills and foundries.

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