This study investigated laser powder bed fusion (LPBF) additive manufacturing of H13 tool steel to identify how laser power (P) and scan speed (V) influenced melt pool geometry, microstructure, and susceptibility to cracking. Sequential studies from tracks, pads to 3D cubes were performed. Tracks and pads were made by laser scan on H13 build plates with and without powder addition. P-V windows were

In orthopedic surgery, thermal damage of bone affects the accuracy of the prosthesis fixation and delays the postoperative recovery time. In order to avoid thermal damage in high-speed bone machining, it is necessary to establish an effective relationship among machining parameters, tool parameters, and temperature distribution of bone materials. Based on the characteristics of bone material and high-speed

The new method of micro-shaft fabrication, named twin-mirroring-wire tangential feed electrical discharge grinding (TMTF-WEDG), is mainly characterized by the tangential feed strategy and the narrow slit formed by twin-mirroring-wire to achieve the diameter control of micro-shaft. The critical factors of micro-shafts accuracy and repeatability include processing position offset of micro-shaft, front

A two-phase Eulerian-Eulerian volume-averaged model was used to predict the outcome of the twin-roll casting process for inoculated Al-4 wt.% Cu alloys. The model is able to address the deformation of the mush during hot rolling by treating the solid/liquid mixture as a viscoplastic skeleton saturated with liquid. A parameter measuring the mean absolute deviation around the nominal composition was

This article investigates picosecond and sub-picosecond laser micromachining of Borofloat®33 glass and provides clear evidence that a simple modification of the laser beam scanning strategy can lead to significant improvement of machining efficiency and hence process throughput. Besides studying the impact of the fundamental laser machining parameters, such as laser fluence, pulse overlap, pulse repetition

Localized heat treatments via Joule effect were performed on cold-drawn NiTi strips to produce a functionally graded material (FGM). Three zones where locally heat treated at 300, 350, and 400 °C for 10 min followed by air cooling. Multiscale and multiphenomena characterization of the obtained FGM was performed through infrared temperature testing, four-point probe and eddy current testing, mechanical

A simple and efficient semisolid slurry preparation technique, called distributary-confluence channel (DCC), was developed to prepare high-quality semisolid slurries of aluminum and magnesium alloys. The DCC process was coupled with the use of a high pressure die-casting (HPDC) machine to successfully achieve near-net forming and implement production applications with rheological high pressure die-casting

1045 carbon steel and 30CrMnSiNi2A high-strength low-alloy (HSLA) steel were joined successfully using inertia friction welding. The effects of the rotational speed on the microstructure and mechanical properties of the joints were investigated. With increasing rotational speed, the tensile strength first increased and then decreased. The weld samples with the highest tensile strength (713 MPa), largest

A method of controlling droplet transfer by plasma arc was proposed to solve the problem that cathode spot force hindered the transition of cathode droplet under high current of twin-wire indirect arc (TWIA) in skew-coupling arc (SCA) welding. The effects of the plasma arc on droplet transfer were analyzed from the perspectives of plasma arc current (PAC) and plasma gas flow rate (PGFR). The current-voltage

Laser shock peening (LSP) is a surface modification technology to synthesize nanostructures on the surface layer of materials, thereby improving mechanical performances. In this work, a laser additive manufactured CoCrFeMnNi high-entropy alloy (HEA) is processed using LSP. The microstructure evolution during LSP is investigated via electron backscatter diffraction (EBSD) and transmission electron microscopy

NiAl alloy is an important lightweight and heatproof structural material used for the service temperature up to 1000 °C. However, there are huge challenges in fabricating NiAl alloy sheets and forming thin-walled components. In order to solve this problem, a novel process of integrated forming and reaction synthesis using laminated Ni/Al foils as the initial blank was developed for fabricating NiAl

Abrasive waterjet (AWJ) is widely used for machining of advanced (e.g. nickel-based) superalloys as it offers high material removal rates and low cutting temperatures. However, the inadequate surface integrity, e.g. large number of scratches and embedded particles in the machined surface, which would induce severe deteriorations of the materials functional performance, has been one of the greatest

The resistance spot welding (RSW) of advanced high strength steel exhibits a high tendency to fail in unfavorable interfacial fracture. To solve this problem, a novel slightly concave electrode was designed. The RSW joints of Q&P steel obtained with the conventional dome-radius electrode and the novel slightly concave electrode in terms of microstructure, micro-hardness and tensile-shear properties

Thick electrical discharge coatings, also known by the commercial name “MSCoating”, can be applied on complex shapes and cavities to repair components or act as protective coatings. A variant of the EDM process, it can be used to make coatings up to several mm thickness on electrically conductive substrates. In this paper, an insight into the microstructure and formation mechanism is made through the

Due to the lack of thorough understanding of the frictional behavior in microforming processes, there is a significant challenge for the process design and optimization towards smart manufacture of micro products. In the present study, the challenging issue of friction in microforming was revealed from an instance of a micro sheet metal roll forming process, which has been found to be an efficient

In the recent years, the automotive industry has increased the production of small, high-power gas engines as part of several strategies to attain the new “Corporate Average Fuel Economy” (CAFE) standards, while meeting consumer demand for increased performance at the same time. This trend necessitates an improvement in the thermal and mechanical fatigue strength of the aluminium alloys used in manufacturing

An investigation was conducted to understand how different parameters, namely laser power, scan speed and hatch spacing, influence the printing qualities, i.e. surface roughness, porosity and crack density of the nickel-based superalloy Inconel 738LC during laser powder bed fusion. Insufficient overlap, Plateau–Rayleigh instability and Marangoni convection were identified and characterized as the factors

Friction stir welding (FSW) process is currently considered as a promising alternative to join aluminium alloys. Indeed, this solid-state welding technique is particularly recommended for the assembly of these materials. Since parts are not heated above their melting temperature, FSW process may prevent solidification defects encountered in joining aluminium alloys and known as limitations to the dissemination

Aerosol jet printing (AJP) is a promising non-contact writing technology to fabricate customized and conformal microelectronics devices on flexible substrates. However, in recent years, the printed line quality is highlighted as a limitation in the applications of AJP technology. According to previous researches, a line printed with high edge roughness and low cross-sectional area will reduce the resistance

Stator core is one of the parts in the magnetic circuit, which playing an important role in the performance of the electric machine. Commonly the non-oriented electrical steel laminations are assembled into a stator stack by welding to meet the demand of strength at high-speed rotation. However, the effects of residual stress, microstructure change and inter-conduction among laminations introduced

When manufacturing flexible devices, it is quite common that localized necking appears due to the low ductility of the metal sheets used. To delay the inception of such localized necking, several industrial companies have proposed a promising technical solution based on the bonding of elastomer substrates to the metal sheets used in the manufacturing processes. In this context, the comprehensive numerical

Lap joints commonly exist in the welding processes during manufacturing of automobiles and ships. Their asymmetric structures make it extraordinary difficult to monitor the penetration states online. In this paper, a two-channel arc sound signal acquisition device is developed and a binaural auditory perception model is proposed to identify the penetration states of lap joints. Firstly, an auditory

A multi-track single crystal structure produced by laser cladding can be succeeded on a flat but failed on complex geometry for single crystal superalloys repair. It was always accompanied with stray grains and cracks when the complex shape defects were repaired by laser cladding. According to analysis, the geometrical profile of the defect may change the heat dissipation condition during laser cladding

The most important challenges when machining difficult-to-cut alloys used in critical applications consist mainly in increasing tool life as well as improving the component surface integrity. In particular, the nickel based alloys exhibit very low thermal conductivity inducing higher cutting temperature and thereby rapid tool wear. In this context, cryogenic machining is a promising approach that enhances

Al-SiC metal matrix composites (MMCs) are promising materials for aerospace and electronic packaging applications. However, machining of Al-SiC MMC is very challenging, often resulting in surface scratches by the hard SiC particles and extensive tool wear. Recent approaches of laser assisted machining using low cutting speeds and low laser power densities, although reduce the tool wear, lead to overheating

Experimental tests were carried out to evaluate and compare welding bead characteristics depending on wire’s oscillation frequency in the GTAW with dynamic wire feeding. Two constant currents (200 A and 250 A) and three frequencies (0 Hz, 5 Hz and 18 Hz) were used to lay an Inconel 625 filler metal over ASTM A36 steel substrates. The weld metal microstructure analysis was based on Scanning Electronic

This paper proposes a double-wire pulsed gas metal arc welding (GMAW) process with a median current waveform based on traditional double-wire pulsed GMAW. A high-speed digital camera and digital oscilloscope were used to simultaneously record the metal transfer process as well as the voltage and current waveforms under different median currents. The median pulse was modeled as an exponential function

Wire-arc additive manufacturing has become an alternative way to produce industrial parts. In this work 15 kg walls are built with an effective building rate of 4.85 kg/h using an ER100 wire providing good tensile properties and toughness under welding conditions. The thermal evolution of the walls during manufacturing is measured by thermocouples and an IR camera: it depends on process parameters

Ultrasonic flexible bulging process based Ethylene-vinyl acetate (EVA) soft medium is presented for fabricating the surface texturing with 3 dimensional shape using ultra-thin metallic sheet of 50 μm in thickness. Advantages of ultrasonic vibration and flexible forming are both utilized to guarantee the forming quality of big area surface texturing, i.e. spherical caps. Effects of ultrasonic vibration

In this study, the coupling effect of magnetic nanofluids and micro-textures under magnetic field on the tribological properties of uncoated tool is revealed for the first time. The micro-scale grooves parallel to the main cutting edge were fabricated on the tool rake face by laser processing (named TP), and for comparison the tools without surface texturing (named NT) were also prepared. Magnetic

A method using backward extrusion of a cylindrical cup to evaluate the anti-galling ability of a zinc phosphate coating is proposed. In this method, galling generation on the inner surface of the cup is judged by the rapid increase in the extrusion load in the extrusion load-stroke diagram. By using a divided punch, the tip of the punch is left at the extrusion end when the main body of the punch is

The innovations in smart packaging will open up a wide range of opportunities in the future. This work describes the processing of additive manufactured and planar integrated polymer optical waveguides for use in smart packaging products. The previously published combination of flexographic and Aerosol Jet printing is complemented by thermoforming and thus creates three-dimensional integrated multimode

The continuously growing demand for micro-electro-mechanical systems (MEMS) with decreasing feature sizes necessitates adjusted manufacturing solutions. Micro-milling fulfills the high requirements for precision and reliability placed on the final product. The employed tools have diameters in the range of 50–300 μm and are commonly manufactured by grinding. However, a reduction in tool diameter leads

In this study, the effects of ultrasonic nanocrystal surface modification (UNSM) treatment on the surface integrity, microstructures and wear resistance of 300M ultra-high strength steel (300M steel) were investigated. The results showed that surface roughness of 300M steels after UNSM processing was significantly decreased with a lower scanning speed even though the surface roughness values were higher

A Pin-plunging reinforced refill friction stir spot welding (P-RFSSW) technique was introduced in this study in order to solve the problem of the central void defect and the alclad residues in the weld center associated with conventional refill friction stir spot welding (C-RFSSW) of dissimilar alclad aluminum alloys. The P-RFSSW process is based on promoting the plastic deformation in the weld center

The effect of carbon content on the precipitation and distribution of intermetallic compounds in titanium to decarbonized carbon steel brazed joint was studied. In this work, decarbonization treatment was employed to change the carbon content in the low carbon steel surface and thus influence the diffusion behavior of Ti and Fe elements in the joint. The microstructure, fracture surface and bonding

δ ferrite and residual stress are known to affect the corrosion behavior of AISI 304 stainless steel welds. To improve the corrosion resistance of a weld, shot peening is often carried out. This study aimed to investigate the effect of shot peening time on the residual stress evolution in both δ ferrite and γ austenite in a 304 stainless steel weld. The residual stresses of both δ and γ phases were

The use of high stiffness plastics to reduce the weight of mechanical systems has been implemented in various industrial fields. As a result, several studies to increase the adhesion strength of metal/polymer joints to improve the mechanical robustness of a system have been reported. In particular, as an alternative to existing adhesive bonding methods, research on the direct molding method has emerged

A novel method of fabricating Ni/WC coatings by laser deposition with a tubular cored wire was proposed and the feasibility was demonstrated in this paper. The wire transfer behaviors with different wire-beam distances and processing parameters were observed via a high-speed camera. A process map was developed to elucidate the dependence of wire transfer modes on the different combinations of operating

Metal-matrix composites (MMC) of a 2000-series aluminum alloy coupled with AlN were fabricated through a commercially-relevant aluminum powder metallurgy (APM) approach. Cylindrical preforms containing 0–5 vol% AlN were produced to investigate the mechanical properties and microstructure evolution through hot upset forging. Specimen were deformed to a maximum strain of 0.15–1.55 mm/mm at rates of 0

In order to alleviate the macrosegregation during the solidification of ingots, an additive casting process called layer casting (LC) was previously proposed. The experimental results show that the macrosegregation had been greatly improved, however, the understandings of the solidification process and the improvement mechanisms of the macrosegregation under the LC method are still lacking. In this

Laser direct metal deposition (DMD) is an efficient and flexible additive manufacturing technique which has broad application prospects, but it is also limited due to defects and mechanical anisotropy. Laser remelting (LR) is a process that after each layer is deposited, re-scan the deposition layer with the same slice data but without powder deliver, and it is often used during selective laser melting

Different coating technologies imply a large variation in the properties of the deposited material. This work compares, for the first time, the wear and corrosion performance of Stellite 6® coatings applied onto substrates of low carbon steel by the Gas Tungsten Arc Welding hot-wire cladding and by High Velocity Oxygen Fuel spraying technologies. The impact of the microstructure and mechanical properties