Showing papers in "Physics Procedia in 2011"

TL;DR: In this article, the authors proposed an additive additive manufacturing (AM) technology that enables the production of light weight structured components with series identical mechanical properties without the need for part specific tooling or downstream sintering processes, etc.

TL;DR: In this article, the influence of process parameters in SLM (e.g., scan speed and layer thickness) and various age hardening treatments on the microstructure and mechanical properties of 18Ni-300 steel is investigated.

TL;DR: In this paper, a comparative study of the ablation of metal with micro-, nano-, pico-and femtosecond laser pulses was presented, where the authors attributed the generally lower medium laser power of the ultrafast laser systems, on the other hand to the changed ablation mechanisms.

TL;DR: In this paper, the effects of the processing parameters such as hatch distance on surface morphology are analyzed, and the results show that the properties of the manufactured parts depend strongly on each single laser-melted track and each single layer, as well as the strength of the connections between them.

TL;DR: The applicability of an aluminium alloy containing scandium for laser additive manufacturing (LAM) is considered in this article, where the development, production and testing of parts built up by a laser powder bed process are presented with regard to the qualification of the new material concept “ScalmalloyRP®” for LAM.

TL;DR: In this paper, the design of an optical system capable of monitoring high scanning velocities and melt pool dynamics is introduced as a first step to the integration of a monitoring and control module into a SLM-machine.

TL;DR: A novel approach to extreme lightweight design is realized by incorporating structural optimization tools, bionic structures and LAM guidelines into one design process and designers can achieve lightweight savings in designing new aircraft structures.

TL;DR: In this article, the feasibility of introducing high strength aluminium alloys and custom developed Al powder systems to the Selective Laser Melting (SLM) process was investigated using a low power fiber laser.

TL;DR: In this article, the influence of curing temperature and curing time on the properties of a kaolin-based geopolymer was studied, and compressive strength and SEM analysis of the products were evaluated.

TL;DR: In this paper, fly ash-based geopolymers required heat to increase the geopolymerization process in order to obtain higher compressive strength, and they were prepared using different curing temperatures, in which sodium silicate and NaOH were used as alkaline activators.

TL;DR: In this paper, a new approach to overcome the problems of state-of-the-art technologies is using laser radiation to ablate the metal surface in order to create microstructures with undercut grooves.

TL;DR: In this paper, an overview of the state of the art and the latest results for cutting, welding and drilling achieved at the IFSW of the University of Stuttgart is presented.

TL;DR: In this paper, a thermo-elastic model for calculation of residual stresses is proposed and experimentally validated, which explains formation of two systems of longitudinal and transversal cracks observed in experiments.

TL;DR: Ablation characteristics of copper and stainless steel with laser pulses from 10 to 100 ps at 1064 nm wavelength were studied in this article, where the influence of the pulse duration and the number of pulses on the threshold fluence and the penetration depth was investigated.

TL;DR: In this paper, a study of the laser cladding of powder metallurgical tool steels has been carried out using a Nd:YAG laser for repairing purposes using optical and scanning electron microscopes.

TL;DR: In this article, a high-power picosecond laser system operating at different wavelengths (355 nm, 532 nm and 1064 nm) has been used for carbon fiber reinforced plastics ablation experiments to study the influence of different laser parameters in terms of machining quality and processing time.

TL;DR: In this paper, the influence of the green wavelength on energy coupling during heat conduction welding and deep penetration welding as well as the influence on the weld shape has been investigated, and it was shown that green laser radiation shows a considerable higher absorption at room temperature.

TL;DR: In this paper, the melting behavior at metallic mixed joint, seam geometry, meld pool turbulence and solidification behavior can be influenced by a high frequent time-, position-and power-controlled laser beam oscillation.

TL;DR: In this article, the restoration of turbine blade knife-edges with controlled laser aided additive manufacturing (LAAM) process was investigated, and the results showed that the process control can also guarantee a better dimensional accuracy.

TL;DR: In this paper, the potentials of numerical simulations for understanding dynamics in laser material processing are discussed, and simulation results on several processes like laser beam deep penetration welding, drilling, or cutting are compared with experimentally obtained data.

TL;DR: In this paper, laser welding technologies for difficult weldable high strength aluminum alloys, containing Cu and / or Li, were evaluated on T-joints of the alloy 2139.

TL;DR: In this paper, the authors introduced a perpendicular heat flow model which describes the sublimation process providing a 1-dimensional analytical solution of the heat conduction equation, which is used to calculate the minimum achievable damage in the matrix material.

TL;DR: In this paper, a 1μm and a frequency doubled thindisk laser were combined to exploit the low absorptivity of ∼1μm laser *beam sources in copper materials.

TL;DR: In this article, a lattice structure was applied on the surface of a medical implant to increase osseointegrative behavior, which can be used to fabricate lattice structures to achieve a modified implant surface.

TL;DR: In this paper, a novel AlxFeCoNiCuCr high-entropy alloy system was manufactured as the thin layer of the substrate by laser cladding; also high temperature hardness, abrasion performance, corrosion nature of the AlxCoNiCNiCCr high entropy alloy were tested under the different ratio of aluminum.

TL;DR: In this paper, a new chamber for laser welding under low vacuum conditions achieved by using rotary pumps was developed, and high-power disk laser bead-on-plate welding was performed on Type 304 stainless steel or A5052 aluminium alloy plate at the powers of 10, 16 and 26 kW at various welding speeds under low-vacuum conditions.

TL;DR: In this article, the authors describe the tribological properties of laser-induced periodic surface structures (LIPSS) and the description of their properties in order to facilitate the knowledge for contact mechanical applications.

TL;DR: In this article, the influence of laser power modulation during copper welding on weld imperfections is discussed and it is shown that a sinusoidal power modulation leads to a strong reduction of melt ejections and also to an increase in penetration depth.

TL;DR: The mechanisms leading to process pores in deep penetration laser beam welding are discussed in this paper, where high-speed videos were recorded and subsequently analyzed, and several interesting insights concerning fluid flow and pore generation could be obtained.

TL;DR: In this paper, a new approach to structuring metallic surfaces with laser radiation is structuring by remelting and another approach of enhancing the appearance of design surfaces is creating a two-gloss effect by selective laser polishing.