Showing papers in "Physics Procedia in 2013"

TL;DR: In this article, a transient three-dimensional beam-matter interaction model was developed to simulate the process dynamics of laser beam melting (LBM) of metals in the powder bed, which was realized by the software OpenFOAM and modified solvers.

TL;DR: In this paper, the authors define some of the process characteristics in powder bed fusion by performing comparative studies with two different test setups, which was done by comparing measured temperature profiles and on-line photography.

TL;DR: In this article, the authors found that the as-fabricated density of parts manufactured from Hastelloy-X by SLM could be increased from 77 to 99% by decreasing the laser scan speed, and that the degree of cracking can be reduced by decreasing minor alloying additions such as Mn and Si.

TL;DR: In this paper, high-speed X-ray imaging of the welding process is used to analyze keyhole instabilities with respect to the formation of weld defects such as melt ejections and pores.

TL;DR: In this paper, a novel approach for thermal joining of thermoplastic metal hybrids by means of a combination of mono- and polychromatic radiation was presented, where experiments for transmission and heat-conduction joining were performed.

TL;DR: The high output power of excimer lasers enables a large processing footprint and the high-throughput rates needed in mass manufacturing as mentioned in this paper for laser lift-off is an enabling technology for microelectronics growth markets such as light emitting diodes, densely packaged semiconductor devices, and flexible displays.

TL;DR: In this paper, a quantitative analysis of spatter formation in laser beam welding with superposed beam oscillation is presented, and an optimal experimental design is created to evaluate spatter characteristics in high speed videos, which is based on automated image data processing.

TL;DR: In this article, the effects of surface inclination angle and strategies to improve the surface finish of LMD components were investigated and a substantial improvement in surface quality of both the side and top surfaces has been obtained by laser remelting after powder deposition.

TL;DR: In this article, the results for polishing of titanium and nickel-based alloys with cw laser radiation are represented in terms of the achievable polishing quality, starting from a roughness of Ra=1μm, a Ra value of 0.16μm was achieved in 7 s/cm 2 for Ti6Al4V and 0.11μm for Inconel718.

TL;DR: In this article, an experimental study of the incubation effect during laser ablation of stainless steel with fs- and ps-pulses at high repetition rates was carried out.

TL;DR: In this paper, the phase formation of Ni-Cr-B-Si laser deposited coatings primarily depends on the Cr content and Si/B ratio with the former controlling the amount of Cr-rich precipitates and the latter influencing the nature of the eutectic structures.

TL;DR: In this paper, a polygon based scanner system incorporating laser and scanner synchronization is presented, enabling writing speeds of 50 m/sec and higher, which is faster than the commercially available galvo-based laser scanners.

TL;DR: In this paper, an approach for the estimation of the powder layer thickness is proposed; optimum thicknesses are derived; the findings are applied to interpret observations that have been made during laser micro sintering of molybdenum powder.

TL;DR: In this paper, a diode laser was used to enhance the absorption of the Nd:YAG welding laser due to preheating by the diode, and the results showed a decreasing number of defects and additionally an increase of welding quality.

TL;DR: In this paper, the rotational movement is produced using a Dove prism, mounted in a high speed, hollow shaft motor, and different kinds of holes are drilled and investigated with respect to hole-quality and drilling time.

TL;DR: In this paper, the effects of three heat treatment technologies on microstructure and mechanical properties of the Ni-based superalloy Inconel 625 samples were investigated. But the plastic property was inferior due to the existence of brittle Laves phase.

TL;DR: In this article, the effects of applied load and sliding time on the friction coefficient and wear loss of a 30wt% short glass fibers (GF) reinforced by polyetheretherketone (PEEK) were examined.

TL;DR: In this paper, surface pre-treatment is used to remove residues of release agents that are transferred to the surface during manufacturing, and analytical experiments, namely SEM and XPS, performed on CFRP surfaces pre-treated with 308 nm excimer laser radiation.

TL;DR: In this paper, the manufacturability of single melt tracks and the buildup of thin wall structures consisting of a few aligned scan tracks is investigated by characterizing single melt track and the build-up of the wall structure.

TL;DR: In this article, the melting of overhang layers has been investigated under full temperature monitoring, and the mechanisms of the melting penetration into the powder bed have been determined, and temperature regimes of the selective laser melting process of the 3D object from steel 316L powder also have been investigated.

TL;DR: In this paper, the antiwear and reducing friction performances of both basic lubrication oil and basic liquid with nano-copper in different mass were tested by friction wear test machine. And the function mechanism of Cu nanoparticles was studied in the paper.

TL;DR: In this article, it was shown that sub-ns pulses could be an attractive alternative to machine steel compared to fiber-based systems with ∼50 ps pulse duration, as no crater formation was observed and the surface quality was better than for 1.4 ns pulses.

TL;DR: In this article, the authors compared the cutting capabilities of a fiber and a CO2 laser beam with similar Rayleigh length with respect to achievable maximum cutting speed, cut edge surface roughness and cut kerf geometry, finding that the cut kerfs are nearly identical in size but differ qualitatively in shape for both laser teypes.

TL;DR: In this paper, the use of a Q-switched fiber laser for surface texturing for tribological, adhesion and biomedical applications is demonstrated and the required surface pattern of the application is investigated along with the processing conditions to realize the pattern.

TL;DR: A new facility for combined neutron imaging and neutron diffraction called IMAT is currently being built at the pulsed neutron spallation source ISIS in the United Kingdom as mentioned in this paper, which will be available for a wide range of materials science applications with a main emphasis on engineering studies.

TL;DR: Alginate and chitosan nanoparticles were synthesized by ionic gelation of the polymers in the presence of stabilizers (PEG 1500, PEG 6000, TWEEN 80) as discussed by the authors.

TL;DR: In this paper, the point at which the laser beam between the two magnetic poles hits the workpiece surface is crucial to the influence of the magnetic field on the weld surface roughness.

TL;DR: In this paper, the authors developed a testing structure system to assess and to characterize the fine patterns of PEDOT:PSS. The testing structures were deposited on various substrates; the transparent flexible polymer foils (polyethylenterephtalate and polyethylenenaphtalene) and also on the glass substrate.

TL;DR: In this paper, the authors investigated Ge 2 Sb 2 Te 5 (GST225) amorphous thin films doped with Bi, Sn and In, using Raman scattering spectroscopy, to obtain information about structural changes after doping.

TL;DR: In this article, Li-Aided Additive Manufacturing (LAAM) was used for the deposition of Ni-base Inconel 625 mixed with nano-TiC powders using laser aided additive manufacturing.