In previous work, laser polishing indirect-SLS metal parts was achieved using a Nd:YAG laser raster scanned at high speed. This work showed surface roughness could effectively be reduced by means of shallow surface melting. Surface area roughness data, Ra, was obtained by line profilometry measurements of the polished samples according to a modified procedure based on the ASME standard for surf...

In laser material removal using a continuous wave or long-pulsed laser, the primary material removal mechanism is melting with molten metal often ejected by an assist oxygen jet. Interactions between heat transfer, oxygen diffusion and gas dynamics have been studied. In laser machining using a Q-switched solid-state laser with pulse width in the order of nanosecond, the primary material removal...

The physical mechanisms responsible for the formation of nanobump structures on a surface of a thin metal film irradiated by a tightly focused femtosecond laser pulse are investigated in a large-scale molecular dynamics simulation. The simulation is performed with a combined atomistic-continuum model adapted for an adequate representation of laser-induced processes at the length-scale of the en...

Introduction: The main purpose of the present study was to describe the ultra structural changes which happened after treatment of the root surfaces with ultrasonic and hand devices followed by Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) laser irradiation. Methods: Sixty single-rooted maxillary and mandibular teeth which had been extracted due to periodontal problems were collected. Crown and...

Iron oxide (FeO) is an important component in the mineralogy of Earth's lower mantle, and possibly its core, so its phase diagram is essential to models of the planet's interior. The melting curve of wüstite, Fe0.94O, was determined up to 77 GPa and 3100 K in a laser-heated diamond anvil cell. Melting transition temperatures were identified from discontinuities in the emissivity vs. temperature...

In terms of heat transfer, the fundamental question raised in this chapter is whether essential features of pulsed laser melting and resolidification at the nanosecond time scale can be described using a thermal model. Of specific interest is the description of the transient melting front propagation as a function of the induced temperature field. Several techniques have been developed to probe...

Anodes of 304 stainless steel have been processed by a continuous wave Yb fiber laser with a wavelength of 1.064 lm and subjected to 50 keV electron bombardment in order to determine the extent to which hydrogen outgassing is reduced by the laser surface melting treatment. The results show a reduction in outgassing, by approximately a factor of four compared to that from untreated stainless ste...

A novel laser rapid thermal annealing (LRTA) technique is reported to tune the plasmonic resonance of disk-shaped nanoporous gold (NPG) nanoparticles for the first time. LRTA alters both the external and internal geometrical parameters of NPG nanoparticles at temperatures significantly lower than the melting temperature of bulk gold or non-porous gold nanoparticles. With increasing annealing la...

A hybrid computational model combining classical molecular dynamics method for simulation of fast nonequilibrium phase transformations with a continuum description of the laser excitation and subsequent relaxation of the conduction band electrons is developed. The model is applied for a systematic computational investigation of the mechanisms of short pulse laser interaction with bulk metal tar...

In this paper, we describe systematic detailed considerations of the feasibility of using various metal nanoparticles for organic-matrix-free surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). In order to avoid the influence of organic molecules on the nanoparticles, stabilizer-free bare nanoparticles of Ag, Au, Cu and Pt were prepared by laser ablation. Although all met...