The depth homogeneity of laser-treated zones is one possible factor to define the quality and efficacy of altered mechanical properties in materials. For instance, half-rounded cross-sectional shapes of laser hardened zones using Gaussian beams provide dissimilar hardened depth in the edges and center of the treated area. This means that the in-depth distribution of compressive residual stress varies

Direct metal laser sintering is a kind of laser powder bed fusion process that emerged as an advanced manufacturing process in the recent era of industry 4.0. This is a rapid manufacturing process where repeated melting and solidification takes place during scanning of the powder bed. The characteristics of the as-built component depend on the melting and solidification behavior which is directly influenced

The microstructural optimization of lithium-ion battery (LiB) electrodes has recently gained a lot of interest. Versatile approaches to enhance fast charging abilities of LiB electrodes are the subject of current research. One of these approaches is the laser based photothermic removal of superficial inactive electrode components in order to improve the accessibility of the active material particles

The effect of pulsed laser polishing on rough niobium surfaces was investigated. We created different well-defined roughness profiles with standard emery papers and subsequently remelted random surface areas with a size of about 2 × 2 mm2 with nanosecond laser pulses (wavelength of 1064 nm, pulse length of 10 ns). Pristine as well as laser-treated surfaces were investigated using optical profilometry

A laser hazard evaluation compares the potential laser exposure to the maximum permissible exposure (MPE). Direct intrabeam viewing of a collimated laser beam produces a minimally sized retinal image. Viewing other laser sources often produces a larger retinal image known as an extended source. An optical limiter is designed to protect the eye from direct laser exposure through a combination of absorption

This paper presents an investigation into the influence of laser drilling on the tensile strength of carbon fiber reinforced plastic (CFRP) laminates of 1 and 2.5 mm thickness. The CFRP laminates were drilled using the microsecond laser, nanosecond laser, and picosecond laser, and the heat-affected zone (HAZ) was characterized and measured by optical microscopy. Through setting laser parameters, specimens

Aluminum alloy is considered to be one of the ideal materials for light-weighting on aerospace and new energy automotive. Laser welding without a filler wire is an efficient way for weight reduction. The common defects in laser welding of aluminum alloys are porosities and cracks, resulting in poor mechanical performances and short service life of joints. In order to investigate the methods to suppress

Laser selective metallization of ceramics (LMC) has been widely applied to prepare high-quality electrical patterns on ceramic circuit carriers. As the dominating factor, surface roughness after laser treatment is controlled mostly by the laser technical parameters, such as laser power, scanning velocity, and laser frequency. Therefore, establishing an accurate relation between the surface roughness

The temperature distribution characteristics of a moving annular hollow laser beam irradiated on the substrate are studied in this paper. First, through the linear superposition property of potential function, we derive the analytical solution of temperature distribution and the cooling rate of the moving ideal annular hollow heat source. The entransy dissipation rate per unit volume of the annular

Commonly, the low wear resistance of stainless steels damages them during usage; in order to enhance wear properties, various types of tungsten-carbide-based coatings, such as WC-Co and WC-Ni, could be applied on the steel surface. To improve the mechanical properties of the coatings, instead of nickel- or cobalt-bearing coatings, WC-FeAl composite coating is used. Following the previous studies on

Laser cutting of metals has become the reference manufacturing technology in sheet metal working thanks to the flexibility and the increased productivity it offers when compared with other competitive technologies. Considering, in particular, the fusion-cutting mode, i.e., when nitrogen is used as an assisting gas, different aspects contribute to the process quality among which dross attachment plays

This paper is the first report of advancement in the drastic reduction of the laser power density from 105 to 7.5 W/cm2 for the synthesis of silver nanoparticles (SNPs) using a low power (60 mW) continuous-wave (cw) laser and a specially designed ultralow duty cycle (3%) optical chopper wheel for modulating the laser beam at low frequencies (2 Hz). The target is irradiated by keeping it in a liquid

Stainless steel has been used as a successful biomaterial for decades. In this study, a pulsed nanosecond laser was used to create patterned surfaces of stainless steel coupons to study the effect of patterning on fluid retention and biocompatibility studies of laser patterned and control surfaces. An AVIA 355 nanosecond pulsed laser was used with different laser parameters to create unique “peak and

Due to the continually increasing popularity of metal powder-based additive manufacturing as a production process in recent years, there has been growing research into improving the surface quality of the parts manufactured in this way. Laser polishing offers great potential as a finishing technique due to its flexibility and suitability for automation. However, the complexity of components that can

The use of as-rolled cold forming steels opens new potential for lightweight construction in the automotive industry. Cold-rolled grades with a tensile strength up to 1100 MPa are on the market. However, the high strength limits the cold forming performance. A local softening in areas of high degree of deformation can be a solution to this conflict. In this work, basic studies on softening of a sheet

Perovskite oxides offer efficient photocatalytic properties for CO2 reduction to methanol. In this study, LaMnO3+δ nanocrystals were fabricated by the solgel combustion method. The structural properties including lattice constants, occupancies, Mn–O lengths, and Mn–O–Mn angle were studied by Rietveld refinement. Jahn–Teller distortion and O-2p and Mn-3d hybridization have been investigated using the

The main purpose of this paper is to use the laser-induced breakdown spectroscopy (LIBS) technique as a fast, noninvasive, and low cost spectro-biochemical analysis laser spectroscopy technique. This study will indicate the qualified performance of LIBS with the proposed optimum conditions as a promising and easy tool for identification, detection, and characterization of trace elements in different

The recent availability on the market of industrial, reliable, ultrashort pulse lasers (UPLs) delivering hundreds of watts has opened the possibility for this technology to significantly increase the machining throughput and address an ever-larger number of industrial applications. Nevertheless, heat accumulation phenomena are observed as soon as the average power P exceeds tens of watts, compromising

In this paper, the skin-core combined with the triple contour method is proposed to solve the density and roughness problems of selective laser melting. Based on the skin-core strategy, the surface roughness is optimized by laser parameter adjustment, and the high-quality side-surface formation is achieved by the triple contour method. The results showed that the relative density increases first and

Laser directed energy deposition (LDED) is one of the metal additive manufacturing processes for fabricating complex shaped metallic components directly from a digital model using high power lasers and metallic powder. To fabricate components with minimum inaccuracies in build geometry and maximum build economy, optimization of process parameters is significant. In the present work, an experimental

In this work, we introduce a simple and universal optical setup design for laser surface texturing (LST) that provides functionality superior than direct laser interference patterning (DLIP). The method requires only a single periodic diffractive optical element and a focusing lens while enabling unlimited freedom for spatial shaping and amplitude variations. The concept is based on the special behavior

This study focused on the potential of topology optimization (TO) for metallic tertiary structures of spacecrafts produced by the additive manufacturing (AM) technique laser powder bed fusion. First, a screening of existing conventionally manufactured products was carried out to evaluate the benefits of a redesign concerning product performance and the associated economic impact. As a result of the

A routine for color marking using oxide layers and laser-induced periodic surface structures is presented. Titanium and alloys thereof are marked with pixelated graphics at a high resolution with tempering colors. A computational approach for the laser path calculation enables a fast-forward marking of complex designs. The color map attained from a laser parameter studies enables vivid coloration.

Solid-solution and carbide-strengthened superalloys such as Haynes 230 are the materials of choice for the hot-section components of gas turbines, e.g., combustion cans and transition ducts. Under severe thermal conditions, to which those parts are exposed, creep strength is a crucial property of the related materials during their lifetime. Recently, the introduction of serrated grain boundaries in

The geometry of the cutting front and the cutting kerf was measured with an online high-speed x-ray diagnostic system. X-ray videos from fusion cutting of 10 mm thick stainless steel samples were recorded with a frame rate of 1000 Hz. A three-dimensional reconstruction of the time-averaged geometry of the cutting front and cutting kerf out of these images made it possible to apply ray-tracing for calculating

Additive manufacturing processes have the potential to produce near-net shaped complex final parts in various industries such as aerospace, medicine, or automotive. Powder bed based and nozzle based processes like laser metal deposition (LMD), laser powder bed fusion (LPBF), and electron beam melting (EBM) are commercially available, but selecting the most suitable process for a specific application

The authors report on surface modification by laser-induced periodic surface structures of different periodicities and modulation depths to modify dry and lubricated tribological properties. Using 220 fs laser pulses in the infrared ( λ 1 = 1030 nm), visible ( λ 2 = 515 nm), and ultraviolet ( λ 3 = 343 nm) spectral regions, the authors periodically structure two-dimensional areas with periodicities

The present study explores an experimental investigation of dissimilar welding of austenitic stainless steel (AISI 316) with nitinol (NiTi) plates by inserting copper (Cu) as an interlayer using a fiber laser system. The presence of copper influences controlling the formation of brittle intermetallic compounds forming compounds of copper with iron, titanium, and nickel. The weldments are examined to

The original morphology of the oxide layer and the surface of the titanium alloy has a significant impact on manufacturing and processing. The laser cleaning pulse frequency amplitude affects the single pulse energy. It will affect the original morphology of the surface and the compositional changes of the laser-generated oxide layer. This work aims to study the effect of pulse frequency on the surface

Laser-induced breakdown spectroscopy (LIBS) is a sensitive optical technique capable of rapid multielemental analysis. The development of this technique for elemental analysis in traditional Chinese medicine can eventually revolutionize the pharmaceutical industry. The detection and identification of real and fake elements in traditional Chinese medicine is very important, and saffron is a typical

The authors characterize femtosecond laser single-pulse machining of deep, micrometer-diameter holes and long, micrometer-width channels in fused silica by the use of spherical, cylindrical, and aspheric singlet lenses. Repositionable spherical lenses form an adjustable beam expander that also provides a means of minimizing—or deliberately introducing—spherical aberration (SA) in the focal region by

In this paper, fiber laser-arc hybrid welding plasma was studied by using the multiple-imaging method. Four images of plasma with different light intensity areas can be simultaneously observed in a picture. The arc plasma and metal plasma can be distinguished in the high light intensity area, and the arc plasma has an approximate average light intensity distribution. The metal plasma is mainly concentrated

Laser cleaning of rusted surfaces has broad applications in marine ship industrial manufacturing. An ultraviolet nanosecond laser cleaning method was proposed to strip the rust layer from the surface of the AH36 steel to reduce surface roughness and increase corrosion resistance. Multi-pulse laser ablation was established to determine the single-pulse threshold fluence and pulse incubation coefficient

Preservation of cultural legacy is essential for ensuring its availability for future generations. Long-term indoor storage can sometimes cause the papers to adhere, which can result in the transfer of ink stamps or prints from paper to paper, and subsequently, there emerges the need to remove these types of stains. Laser cleaning emerged as a promising technique for paper surface cleaning. This work

Several experiments are performed to explore the possible benefits of using bamboo charcoal as a sample holder for rapid powder analysis using laser-induced breakdown spectroscopy at low-pressure helium ambient gas. Standard powdered samples such as ZnS and CuSO4 are used to demonstrate the feasibility of using cheap and widely available bamboo charcoal as a sample holder. A commercial baby milk powder

In order to investigate the overlap rate of an ablated spot on monocrystalline silicon by a femtosecond laser, a skewness spot derived from plasma is analyzed. First, the serial spot image is collected, and the ablated core area of the spot is extracted by the way of bit image layering so that the peripheral halo can be eliminated effectively. The image of the spot is enhanced by Gaussian-guided filtering

The current laser safety standards do not address specifically how to account for repetitively pulsed lasers with irregular pulse trains. Variations in peak power, pulse duration, and duty cycle within a pulse train pose a number of problems when it comes to product classification or to assess the hazard of a given exposure. This study proposes to analyze irregular pulse trains by generalizing the

An electro-optic Q-switched multiwavelength laser diode array end-pumped Nd:YAG laser without temperature control is proposed and demonstrated in this paper. Using a 3.2 kW multiwavelength laser diode array as the pump source, a lens duct as the coupling system, RTP crystals as the Q-switch, and an end-pumped Nd:YAG crystal rod (Ø 6 × 60 mm2) as the gain medium, the laser system obtained a maximum

Developing laser welding (LW) technology in a hyperbaric environment is significant for manufacturing and maintaining nuclear power facilities, offshore engineering structures, etc. However, the penetration is significantly reduced during LW in a hyperbaric environment, which has not been solved yet. Previous research has shown that compared with the penetration of LW in a hyperbaric argon (Ar) environment

Ti6Al4V alloy exhibits good biocompatibility and has a wide range of applications in the medical fields. Additive manufacturing, especially selective laser melting (SLM), provides a new and effective way for the fabrication of Ti6Al4V alloy biological components. The corrosion resistance of SLM processed Ti6Al4V alloy needs further investigation, which is important for the application of biological

Fe-Cr-C near-eutectic alloys are commonly used in wear resistant parts in mining applications, due to their excellent erosion and abrasion wear resistance. Laser metal deposition is an additive technology that presents opportunities for manufacturing mining components, as well as repairing worn areas of wear resistant parts. However, Fe-Cr-C hypoeutectic alloys are very hard and brittle and are often

The study aims to understand the carbonization mechanism when an ns NIR transparent fiber laser beam irradiation of polycarbonate (PC) instead of irradiation using a UV laser beam or ultrashort pulsed laser beam. It reveals that PC can be decomposed with an ns transparent 1064 nm laser beam. The laser fluence threshold under which to cause ablation in PC was not a constant value. The threshold decreased

The influence of wire feeding speed during laser welding with a filling wire was investigated by high-speed imaging and mechanical analysis of the droplet. A force relationship was found to analyze the droplet transition behavior at the end of the welding wire in the narrow-gap groove. Welding defects, mainly including nonfusion and porosity, were studied to reveal the formation mechanism and propose

In the additive manufacturing (AM) process, metal powder can be directly used to produce metal components. Unfortunately, a large thermal gradient is developed during the AM process, which leads to the generation of residual stress and complex shape-distortions. In this study, the influence of the geometrical size and structural features of a hollow Ti-alloy blade prepared by the AM process on the

Phase change heat transfer allows high heat transfer rates associated with small temperature variations. Given that this technique is employed in several energy and industry applications, such as automotive air-conditioning evaporators, pulsating heat pipes are used for aerospace thermal management and in semiconductor-manufacturing heat exchangers. Although phase change heat transfer has served mankind

Remote laser welding (RLW) combines the positive features of tactile laser welding with additional benefits such as increased processing speed, reduced operational cost and service, and higher process flexibility. A leading challenge preventing the full uptake of RLW technology in industry is the lack of efficient closed loop in-process (CLIP) monitoring and weld quality control solutions. This underpins

Additive manufacturing of metal matrix composite (MMC) is a challenging field to explore. Besides components’ geometric constitution, requirements related to final microstructures must be met. Depending on the application, such as tribology, machining, or magnetism related, there is a need to preserve a specific phase, which is generally responsible for the engineering function of the fabricated component

Direct joining of metals and polymers is a promising approach for today’s challenges in joining technology due to fast cycling time, its robustness, and the absence of duroplastic adhesives. Laser pretreatment of the metallic surface has been proven to enhance joint strength and has become a popular method for joining hybrid components. However, the versatility of the laser process allows the generation

Powder based laser material deposition (LMD) is a suitable additive manufacturing technology for repair and overhaul of metal parts as well as for the build-up of new parts. This technology is used in industrial applications as automotive, turbomachinery, aviation, or tool making [T. Jambor, “Funktionalisierung von Bauteiloberflächen durch Mikro-Laserauftrag-schweißen,” Ph.D. thesis, RWTH Aachen University

Laser beam welding significantly outperforms conventional joining techniques in terms of flexibility and productivity. The process benefits, in particular, from the highly focused energy and thus from a well-defined heat input. The high intensities of brilliant laser radiation, however, induce very dynamic effects and complex processes within the interaction zone. The high process dynamics require

Superhydrophobic surfaces have been attracting considerable attention due to potential applications in self-cleaning, anti-icing, water/oil separation, drag reduction, water collection, etc. However, to date, except for a few textile surfaces and coating products, only a limited number of superhydrophobic applications have been commercialized. The main reasons for the limited number of applications

In this work, laser cladding of a Ni-based superalloy powder (Inconel 718) on a Fe-based superalloy (A-286) substrate was performed. The microstructural evolution was studied by optical and electron microscopy techniques, aided by energy dispersive spectroscopy. Additionally, the microhardness along the as-deposited parts was analyzed and correlated with the observed microstructure. It was found that

The formation of self-assembled laser induced periodic surface structures (LIPSSs) after ultrashort pulsed laser ablation is still a matter of controversy in the literature. There is agreement that at least two different physical driving forces lead to ripples with distinguishable spatial periodicity. High spatial frequency LIPSSs with periodicity well below the incident wavelength are discriminated

A novel approach for the reconstruction of an equivalent volumetric heat source from a known weld pool shape is proposed. It is based on previously obtained weld pool geometries from a steady-state thermo-fluid dynamics simulation. Hereby, the weld pool dimensions are obtained under consideration of the most crucial physical phenomena, such as phase transformations, thermo-capillary convection, natural

In this study, using ultrafast lasers of 10 ps pulse duration as a precise and efficient method for cutting edge preparation is researched. Cutting edge preparation is an important step within cutting tool manufacturing, while unprepared sharp cutting edges show low stability, which leads to tool failure by high mechanical and thermal loads during the turning processes [C. F. Wyen, W. Knapp, and K

Material processing by ultrafast lasers is an attractive technology for high-precision fabrication, such as cutting, drilling, and surface modification, of a wide range of material, including dielectrics, semiconductor, metals, and polymer composites. However, it is still challenging to apply ultrafast laser processing in many applications because some key processes, such as absorption and heat accumulation

Problems related to component wear are one of the biggest challenges faced by industrial sectors such as agriculture, mining, and oil and gas. Coating application has been a good alternative to mitigate these problems. Ni-Cr-B-Si alloys are recognized for their abrasion and adhesion resistance properties. In this context, a comparison between the mechanical wear of Ni-Cr-B-Si 1545-00 deposited via

With the rapid development of high-power lasers, efficiency of laser cutting and thickness of cutting material have been greatly increased. In this study, a 10 kW fiber laser was used to cut 18 mm thick 316L stainless steel sheets. The surfaces and cross sections of samples were observed by an optical microscope and a scanning electron microscope. It was found that the quality of laser cutting was

Although different forms of renewable energy sources are in expansion, the oil and natural gas industry remains essential, maintaining its demand for more efficient methods for product transportation. The most productive and safe way is the flow through pipelines. However, pipeline usage directly involves several wear mechanisms, which contribute to pipeline degradation and, consequently, the need

Hybrid laser-arc welding (HLAW) is regarded as a promising joining process, since it can compensate disadvantages from laser autogenous welding and arc welding by uniting both techniques into a single melt pool. Such a process can achieve relative high quality metallurgical bonding, high speed, and low deformation. However, the process is considered complex and of difficult parametrization, as the