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Lasers in Manufacturing and Materials Processing
Journal Prestige (SJR): 0.311  Citation Impact (citeScore): 1 Number of Followers: 2  Subscription journalISSN (Print) 2196-7229 - ISSN (Online) 2196-7237 Published by Springer-Verlag  [2469 journals]
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- Effect of Different Heat Treatment Routes on the Tribological Behavior of
the Inconel 718 Alloy Deposited on Aisi 316 L by Laser Cladding-
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Abstract: The aim of this work was to evaluate the effect of different heat treatment routes on the microstructure and sliding wear resistance of Inconel 718 alloy deposited by laser cladding on an AISI 316 L stainless steel substrate. Three heat treatment conditions were tested: double aged, solubilized and double aged, and homogenized, solubilized and double aged. These conditions were compared between each other and the as built samples. Both as built and double aged conditions presented a dendritic microstructure. The solubilized and double aged samples exhibited a recrystallized characteristic, however still containing a dendritic structure. While the homogenized, solubilized and double aged samples reveled equiaxial grains with the total replacement of the dendrites. Regarding the top and cross-section hardness, the heat-treated claddings were superior (about 65% higher) when compared to the as built condition. The friction coefficient for all conditions were statistically equal, however the solubilized and double aged and homogenized, solubilized and double aged conditions showed better results of wear loss (about 25% lower) when compared to the as built condition, whereas the double aged condition displayed statistically equal results in relation to the others. The wear mechanisms were predominantly adhesive for the as built conditions, adhesive and abrasive for the double aged and mostly abrasive for the solubilized and double aged and homogenized, solubilized and double aged samples. The results presented confirmed the need for heat treatment to improve the hardness of the coating and, in addition, it can be concluded that the different heat treatment routes did not have significant impacts on wear resistance. Therefore, from the conditions tested in this study it is possible to assume that the double aged route is the most suitable, for the point of view of wear resistance.
PubDate: 2022-05-17
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- Creep and Corrosion Characteristics of Laser Welded AA5083 Al–Mg
alloy-
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Abstract: In this work, square butt joints were produced on a 3 mm thick AA5083-H111 alloy using Yb:YAG laser welding technique. The creep and corrosion properties of processed welds were determined through the impression creep test and potentio-dynamic polarization method respectively.The results show that,the formation of porosity remained a severe problem in welds processed with longer shielding gas blown distance. Irrespective of other parameters, the longer shielding gas blown distance alone showed a significant impact on porosity formation. However, the weld processed with a higher laser power at moderate welding speed showed a better creep and corrosion properties at all testing conditions. The existence of Nano-sized Al6Mn and Al6(Fe,Mn) intermetallics along with a high density of dislocations improved the creep and corrosion resistance of the weld. On the contrary, the porosities present in the welds lowered pitting potential of weld surface which reduced the width of passive region and, thereby, results in severe corrosion. Interestingly, porosity comprised of a higher concentration of Fe and Mn particles acted as a localized cathode and remained undamaged even after corrosion. This occurrence made the weld comparable with others in corrosion aspects. The creep rate of welds with porositieswas lower than that of other welds.
PubDate: 2022-05-10
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- AgO Nanoparticles Synthesis by Different Nd:YAG Laser Pulse Energies
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Abstract: Abstract Pulsed Laser Ablation in Liquid PLAL is one of the most effective methods for creating nanoparticles material. The PLAL process was used to make AgO nanoparticles, in which the silver target was submerged in ultrapure water UPW and then irradiated with an Nd: YAG laser (Q-switched, 1064 nm, 6 ns pulse duration). The laser beam was concentrated near the silver surface throughout this operation. The effects of different incoming laser pulse intensities (50, 250, 500, 750) mJ were investigated on the particle size of nanoparticles generated via laser irradiation. Nanoparticles in the nano solution were characterized through Atomic Force Microscope AFM, Ultraviolet-Visible UV-VIS test, PH measurement, and Electrical Conductivity EC test. The smallest particle size was produced with (50) mJ laser pulse energy. A new model is derived to understand the electrical conductivity results at different sizes including nanoscale. The new model brought a new factor proportional to the third degree of grain size. Despite the experimentally yielded low value compared with other factors, it has a valuable role in interpreting the conductivity results at different grain sizes.
PubDate: 2022-04-14
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- Correction to: Droplet Assisted Nanosecond Fibre Laser Micromachining
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PubDate: 2022-04-07
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- Study on Microstructure and Anti-Corrosion Property of Stainless Steel
Particles Deposition on Ti–6Al–4 V Substrate using Laser Cladding
Technique-
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Abstract: Abstract In the present study, the Stainless Steel (SS420) particles is deposited on Ti–6Al–4 V (Ti-64) substrate using laser cladding process. The cladded structure and hardness were analysed through Field Emission Scanning Electron Microscopy (FESEM) and Nanoindenters, respectively. Then, the corrosion behaviour of the cladded surface was analysed with polarization test and electrochemical impedance method with different testing hours (0, 18 and 42 h). Further, the roughness of the corroded surface was measured using laser confocal microscopy. Result showed that the laser cladded surface shows with three structures namely, coaxial dendrites, columnar dendrites and cellular dendrites. The cladding nanohardness (10.58 GPa) was higher while compared with base (4.53 GPa) and interface regions (5.89 GPa). Corrosion current density at 18 h test specimen is lower than that at 0 h and 42 h test specimen and improved the corrosion resistance by forming the passive layer at 18 h test specimen. Moreover, lesser roughness was noticed at 18 h test specimen due to reduced corrosion rate.
PubDate: 2022-03-29
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- Percussion Nd:YAG Laser-incision of Radiata Pine: Effects of Laser
Processing Parameters and Wood Anatomy-
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Abstract: Abstract Laser-incision is gaining recognition in the timber processing industry as a preferred and competitive technique for increasing uptake of chemical and preservative treatments. This work details percussion Nd:YAG laser-incision of Radiata Pine, conducted at different wavelengths, incident laser energies and focal point positions. For the first time, the effect of wood anatomy (latewood and earlywood tissues) on the efficiency and quality of Nd:YAG laser-incision of Radiata Pine is explored. Nd:YAG laser wavelengths of 1064 nm (fundamental wavelength), 532 nm (second harmonic) and 355 nm (third harmonic) were used to understand their effect on laser-incised hole characteristics. A maximum laser-incised hole diameter of ~ 2.5 mm was measured at 1064 nm for 700 pulses. The presence of earlywood and latewood had a distinct effect on hole shape evolution, showing the importance of wood anatomy in the process of percussion Nd:YAG laser-incision. Ultra-violet (UV) radiation (355 nm) was the preferred wavelength for laser-incision of Radiata Pine as it gave rise to less carbonisation, less tapering and a uniform incision along the length of the laser-incised holes. Maximum depth of the laser-incised hole was measured (~ 20 mm) using the 355 nm wavelength. Incident laser energy, wavelength and wood anatomy had a dominant role in laser-incision hole size, shape and quality. This demonstrates the critical effect of wood anatomy on the laser-incision process when considering and utilising laser technology to produce incisions for the wood treatment and wood preservation industries.
PubDate: 2022-03-25
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- Empirical Model for the Description of Weld Seam Geometry in Coaxial Laser
Hot-Wire Deposition Welding Processes with Different Steel Wires-
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Abstract: Abstract Claddings are used to protect areas of components that are exposed to particular chemical, physical or tribological stresses. The aim when developing a cladding process is to achieve a cladding with low waviness in order to reduce the amount of machining required. Computational models and FEA simulations can be used to determine process parameters for claddings with low rework including a prediction of the height and width of a single weld seam aswell as the development of welding strategies. In this paper empirical models describing the geometry of single weld seams on a substrate manufactured with a coaxial laser hot-wire cladding process are investigated for three steel wire materials and different welding parameters. The coordinates of surface points of the weld seams were detected using a laser scanning microscope and post-processed by a self-created script. In order to describe the cross sectional shape of the weld seams, the parameters of parabolic, cosinusiodal or circular arc model functions are derived from the surface data using a fitting algorithm. For the tested wire materials, an effect of the wire material on the shape of the weld seam was not observed. The investigations also show that regardless of the varied welding parameter set or wire material, a circular model function appears to be the most suitable model shape for describing the cross sectional weld seam geometry in coaxial laser metal deposition with hot-wire. The regression residua using a circular arc model function ranged from 18.9 \(\upmu\) m to 34.6 \(\upmu\) m, which indicates a good approximation.
PubDate: 2022-03-25
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- Machinability Analysis and Multiple Performance Optimization During Laser
Micro-drilling of CNT Reinforced Polymer Nanocomposite-
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Abstract: Abstract The present research focuses on presaging the optimal parametric data set (material removal rate (MRR), taper, and heat-affected zone (HAZ)) for laser micro-drilling of a new class of polymer composite consisting of carbon nanotube (CNT) and epoxy. Experiments are conducted according to Taguchi’s methodology with cutting speed, lamp current, air pressure, and pulse width as controllable parameters and their significance is assessed through ANOVA. Second-order nonlinear regression models integrating relationship between control parameters and output responses are developed for optimizing the process parameters. Optimum process parameters are evaluated to minimize taper and HAZ and maximize the MRR. These nonlinear regression equations are further utilized in accelerated particle swarm optimization (APSO) algorithm for single as well as multiple performance optimization. A confirmation test is carried out with the optimal parameter settings obtained from Taguchi’s methodology and APSO and improvement in performance parameter is noticed in each case. It is also observed that the APSO metaheuristic algorithm performs efficiently for optimizing the responses relating to the laser micro-drilling process of nano-composites both in individual and multi-objective optimization.
PubDate: 2022-03-19
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- Secondary electron yield reduction of copper after 355 nm ultrashort
pulse laser ablation-
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Abstract: Abstract Nanostructured surfaces exhibit remarkable chemical, physical and microbiological properties and have therefore various technical and industrial applications. The ultrashort laser pulse irradiation (wavelength λ = 355 nm, pulse duration Δtp = 12 ps, repetition rate f = 100 kHz) of copper samples with appropriate laser parameters results in the formation of a micro- and nanostructured surfaces. The influence of these hierarchically textured surfaces on the secondary electron yield (SEY) was studied especially with regard to their morphological and geometrical properties. Specific SEY changes are caused by both, the shape and the depth of the microstructures, as well as the morphology of the formed nanostructures; that can be either compact flower head-like nanostructures, non-compact filament-shaped nanostructures, molten and resolidified spherical structures, or minor modified surfaces. The measured SEY as a function of the primary electron energy is correlated with the surface topography that forms upon laser irradiation. The SEY decreases with increasing accumulated laser fluence and ablated volume, respectively. Especially flower-head-like nanostructures can be produced at high laser power (P ≥ 400 mW) and low scanning velocity (v ≤ 10 mm/s) and represent a surface with strongly reduced SEY maximum as low as 0.7.
PubDate: 2022-03-03
DOI: 10.1007/s40516-022-00167-5
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- Nanonetworks fabrication by laser ablation in water of bimetallic
compositions of platinum and palladium with gold and silver-
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Abstract: Abstract With the advancement of nanosciences and nanotechnologies, the goal of synthesizing nanomaterials with controllable composition and morphology, and hence optical, electronic and catalytic properties, seems increasingly within grasp. We propose and discuss a methodology for fabrication of bimetallic nanostructures with easily-controllable composition by using nanosecond laser ablation in liquid (LAL) of bimetallic films. Under certain process conditions, bimetallic Au-Pd, Ag-Pd, Au-Pt, and Ag-Pt nanonetworks (NNs) are obtained. TEM analysis shows that the LAL of bimetallic Au-Pd, Ag-Pd, and Au-Pt mainly leads to the formation of NNs, while in the case of ablation of Ag-Pt films, in addition to the NNs spherical nanoparticles are also observed. HRTEM analysis reveals that the NNs are composed of both alloyed sections and monometallic ones. A relative association is established between the relative content of Au and Ag in Pd- and Pt-based bimetallic films and the morphology of the nanostructures formed by LAL. The method presented is promising in view of synthesizing contamination-free nanostructures with complex composition and morphology that could find effective uses in fields such as biomedicine, sensorics, and electrochemistry.
PubDate: 2022-03-01
DOI: 10.1007/s40516-022-00168-4
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- Fabrication of Thin Walls with and without Close Loop Control as a
Function of Scan Strategy Via Direct Energy Deposition-
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Abstract: Abstract Direct Energy Deposition (DED) is a technique used to fabricate metallic parts and is a subcategory of metal additive manufacturing. Despite of its vast advantages over traditional manufacturing the deployment at industrial level is still limited due to underlaying concerns of process stability and repeatability. In-situ monitoring, therefore, is indispensable while depositing via DED. The present experiment is a step towards enhancing our current understanding of the DED when coupled with a closed loop control system to control melt pool width for deposition of thin-walled structures, and as a function of scan strategy. 316L stainless steel powder was deposited on S235JR substrate. A total of 6 iterations are reported, out of many performed, of which 3 were without the closed loop control. Also, to understand the effect of scan strategy as a function of laser power. Two different scan strategies were employed for understanding of the issue i.e., unidirectional, and bidirectional. Apart from the geometrical consistency of the wall, microhardness, density calculations and microstructure were investigated. The geometric consistency was found to be almost perfect with the bidirectional scan strategy. In case of unidirectional scan strategy, the wall shows a negative slope along the other extreme regardless of the closed loop control system. Dilution zone shows the hardness greater than both the substrate and the wall. The specimens fabricated without the use of closed loop control were found to be denser than their counterparts. This was found to be true also in case of manual reduction of power during each layer.
PubDate: 2022-02-01
DOI: 10.1007/s40516-022-00164-8
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- Droplet Assisted Nanosecond Fibre Laser Micromachining
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Abstract: Abstract Nickel alloys are widely used in the high-value manufacturing industry for the production of a variety of components like gas turbine engines. Machining of this type of materials requires a technique that will ensure material removal at a rate appropriate enough to yield the desired finished quality. The conventional nanosecond pulse laser micromachining (PLM) has significant limitations in terms of material removal rate and eventually finished quality. To that concern, droplet assisted fibre laser micromachining (DAFLM) is a new technique that is proposed as an alternative and therefore investigated in this research. The DAFLM technique involves injecting micro-droplets over the laser/material interaction zone to create a shock pressure that enhances the laser machining process. The results of the investigations on the DAFLM technique confirmed that its melt ejection mechanism is enhanced through the interaction between the droplets and laser irradiation, thus portraying the technique to be of higher efficiency with a 97% improvement in material removal rate and a 40% improvement in redeposited spatter reduction compared to the PLM technique.
PubDate: 2022-01-22
DOI: 10.1007/s40516-021-00162-2
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- Crown Glass Drilling by Short-Pulse CO2 Laser with Tunable Pulse Tail
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Abstract: Abstract Hole drilling in crown glass with a large thermal expansion coefficient of 94 × 10−7 /K by a longitudinally excited short-pulse CO2 laser with a tunable laser pulse tail was investigated. The CO2 laser produced short laser pulses with a pulse width of about 250 ns, a pulse tail with a length of 31.4 to 134.7 μs, a spike pulse to pulse tail energy ratio of 1:7 to 1:92, and a fluence per single pulse of 6.0 to 37.9 J/cm2 at a repetition rate of 1 to 400 Hz. Sample cooling was not employed in the drilling process. At a repetition rate of 1 to 90 Hz, the CO2 laser pulses produced cracks. At a repetition rate of 100 to 140 Hz, the CO2 laser pulses occasionally produced cracks and crack-free holes. At a repetition rate of 150 to 400 Hz, the CO2 laser pulses produced crack-free holes. Under various irradiation conditions, the hole depth and estimated hole volume per total irradiation fluence depended on the fluence per single pulse but did not depend on the laser pulse waveform or repetition rate.
PubDate: 2022-01-22
DOI: 10.1007/s40516-022-00165-7
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- Machinability Analysis During Laser Assisted Turning of Aluminium 3003
Alloy-
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Abstract: Abstract Laser assisted turning (LAT) is emerging as a significant process for machining various materials. In this study, experimental analysis is carried out to investigate the machinability of the aluminium 3003 alloy during conventional turning (CT) and LAT processes. The effect of laser beam irradiation on machining performance is analyzed and compared with the CT in terms of machining forces, chip morphology, and surface roughness. The results showed that in comparison with CT, the cutting, thrust, and feed forces could be reduced significantly in LAT. However, these forces were found to be increased at other than optimum laser power. It was pretty interesting to observe that the cutting, thrust, and feed forces were increased at high laser power. Surface roughness was also found to be higher in LAT than that in CT. Chip morphology analysis showed that the discontinuous and thick chips are observed at high laser power, whereas continuous and small chips are observed at low laser power, while continuous and long chips are obtained for CT. The presented results are important for manufacturing industries seeking to improve the machinability of the materials.
PubDate: 2022-01-17
DOI: 10.1007/s40516-022-00163-9
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- Laser Welding of Titanium Grade 2 and Aluminium AA 3105-O Using a New
AlScZr Filler Metal-
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Abstract: Abstract In this study, a pulsed Nd:YAG laser welding method is implemented to join Ti-G2 (1 mm thick) to AA3105-O (0.5 mm thick) via a ring of spots filled with AlScZr alloy (0.15 mm thick). The filler material improved the weld’s microstructure and mechanical properties by reducing the undesirable intermetallic compounds (IMCs) such as TiAl2 and TiAl3 in the aluminium re-solidified zone near the titanium/aluminium interface. The joints having AlScZr filler were mostly failed at Al heat affected zone (HAZ) during the tensile shear test. The addition of zirconium to binary Al–Sc system formed a substitutional solid-solution in which 50 wt% Zr+10 wt% Ti replaced Al3(Sc,Zr,Ti). Scandium had a strengthening effect by solid-solution and precipitation hardening effect due to the formation of Al3(Sc,Zr) particles. The joint strength rose from 86% (of the base Al strip) for autogenously laser weld to 102% with filler metal. Hardness increased steadily at the Ti/Al interaction zone, and the maximum hardness was reduced from 650 HV to 570 HV when filler metal was utilized.
PubDate: 2022-01-09
DOI: 10.1007/s40516-021-00159-x
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- Physicochemical Properties of Nanofluids Produced from Oxidized
Nanoparticles Synthesized in a Liquid by Pulsed Laser Ablation-
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Abstract: Abstract Since pulsed laser ablation in liquid is the most common, simple, and efficient technique to synthesize nanoparticles (NPs). In this work, pure aluminum (Al) and pure copper (Cu) targets are located inside a liquid ambient, next a Nd-YAG Laser of 1064 nm wavelength and 10 Hz pulse repetition is used at four different pulse energies of 30, 50, 70, and 90 mJ to produce Al-NPs and Cu-NPs. After that, a comparative/superlative study, and the physicochemical properties of the prepared nanofluids, (Al-NFs) and (Cu-NFs), have been carried out using transmission electron microscope, scanning electron microscopy with energy-dispersive X-ray spectroscopy, zeta-sizer, UV-Vis spectroscopy, density meter, and viscometer. The influence of laser energy on these properties have been investigated as well.
PubDate: 2022-01-07
DOI: 10.1007/s40516-021-00160-4
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- Parameters Development for Optimum Deposition Rate in Laser DMD of
Stainless Steel EN X3CrNiMo13-4-
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Abstract: Abstract Laser Direct Metal Deposition (DMD) has been developed as a manufacturing process to deposit coatings on existing materials and proves advantageous in Additive Manufacturing (AM) of complex and precise components. However, it is necessary to carefully determine the proper process parameter combinations to make this method economically viable for industries. The intent of this study is to address enhancement in productivity of laser DMD of stainless steel EN X3CrNiMo13-4. Accordingly, the effects of the main laser process parameters of laser power P, scan speed v, powder flow rate \(\dot{\mathrm{m}}\) , and spot diameter s on track geometries and build-up rate are discussed. The regression analysis is conducted to derive correlations between the combined set of main parameters and deposition rate. The results show a good linear regression correlation of R2 >0.9 for the geometrical characteristic of aspect ratio, dilution, and deposition rate. The constructed processing map, using linear regression equations, presents proper process parameters selection in connection with deposition rate, aspect ratio, and dilution rate.
PubDate: 2021-12-01
DOI: 10.1007/s40516-021-00161-3
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- Investigation on Laser Beam Weldability of AISI 304L Plates Based on
Thermal Field Simulation by Experimentally-Fitted Analytical Modeling-
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Abstract: The objective of the work is to present a new approach to the simulation of the thermal field in laser beam welding, based on an experimentally-fitted analytical model, applied to investigate the weldability of AISI 304L austenitic steel. Reference is made to the welding trial in a single pass of two 10 mm thick butt-positioned plates. Welding was performed under the keyhole full penetration mode, which is characteristic of high-power laser beam, and simulated by an analytical model based on a multipoint-line thermal source system and fitted on the experimental fusion zone profile. The model was applied to simulate the effects of welding speed changes on thermal fields and cooling rates, in order to determine how they can affect the weld composition, the solidification mode and the possible formation of a sensitized zone in the heat affected zone. A limit value of welding speed, which allows the weld formation without lack of fusion, was identified. For all the welding speeds considered, the formation of a sensitized zone can be excluded. The contribution of welding speed on cooling rate, not significant near the welding axis, results to be determinant at the boundary of the fused zone with base metal. The combined choice of the filler material and the welding speed, which in all cases gives rise to primary ferrite solidification modes, affects the content of residual ferrite, which must be balanced to enhance the resistance to solidification cracking, avoiding the adverse effects due to too high contents. As a conclusion, the model proves to be a valid support in investigating the thermal effects, which result from the setup of welding parameters, on the weldability of the base metal-filler system. Graphic
PubDate: 2021-10-20
DOI: 10.1007/s40516-021-00157-z
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- Numerical Simulation of Thermal Behavior and Experimental Investigation of
Thin Walls during Direct Metal Deposition of 316L Stainless Steel Powder-
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Abstract: Abstract Direct metal deposition (DMD) is a method of additive manufacturing in which parts are manufactured by melting powder particles that reach the working area, layer by layer, using a laser beam. Thin walls are built by the means of direct metal deposition (DMD) from 316L stainless steel powder. A multi-layer finite element model (FEM) is used to predict the thermal cycles, maximum temperatures, and volume of the molten pool during DMD. The experimental methods and the simulation processes show effects of heat accumulation with the addition of new layers, especially at the beginning and at the end of each layer. The microstructure of the samples is examined by an optical microscope. The experimental results indicate that microstructure has a disorganised form in the outer regions that are closer to the surrounding air, and that grains grow in groups in the inner parts of the samples.
PubDate: 2021-09-07
DOI: 10.1007/s40516-021-00155-1
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- A Comparative Stress Corrosion Cracking Study of Stainless Steel Sheets
Marked with Laser and Conventional Mechanical Stamping-
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Abstract: Abstract This communication reports the result of a comparative study of laser marking with conventional mechanical stamping of AISI 304 stainless steel sheet by subjecting the marked specimens to stress corrosion cracking susceptibility test. A single mode fiber laser was made use of for this work to mark the steel specimens while a hydro-pneumatic press was used to effect marking in the conventional way. Mechanically stamped specimens exhibited better resistance to stress corrosion cracking compared to specimens marked with laser. The cracking susceptibility of laser marked samples was found to be critically dependent on the fluence of laser used to cause marking. Extent of cracking was found to increase with fluence. Reduced stress corrosion cracking susceptibility of mechanically stamped specimens was attributed to the presence of compressive residual stresses in and around the mark. This work establishes that upon scaling down its fluence appropriately, a laser can be a workable tool for marking stainless steel components meant for application in corrosive media.
PubDate: 2021-08-26
DOI: 10.1007/s40516-021-00154-2
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