نتایج جستجو برای: laser melting

تعداد نتایج: 207729  

2017
Rostislav Hrubiak Yue Meng Guoyin Shen

High-pressure melting anchors the phase diagram of a material, revealing the effect of pressure on the breakdown of the ordering of atoms in the solid. An important case is molybdenum, which has long been speculated to undergo an exceptionally steep increase in melting temperature when compressed. On the other hand, previous experiments showed nearly constant melting temperature as a function o...

2003

The threshold laser fluence for the onset of surface melting is calculated for Ni films of different thicknesses and for a bulk Ni target using a combined atomistic-continuum computational model. The model combines the classical molecular dynamics (MD) method for simulation of non-equilibrium processes of lattice superheating and fast phase transformations with a continuum description of the la...

Journal: :Journal of Manufacturing and Materials Processing 2020

2017
Sankhya Mohanty Jesper H. Hattel

Selective laser melting is developing into a standard manufacturing technology with applications in various sectors. However, the process is still far from being at par with conventional processes such as welding and casting, the primary reason of which is the unreliability of the process. While various numerical modelling and experimental studies are being carried out to better understand and ...

2011
Bin Liu Yuxin Li

A novel preparing method of polymer-coated molybdenum powder was presented. A type of multi-component polymer-coated molybdenum powder was chosen for selective laser sintering. The effect of the process parameters on the part’s characteristics is investigated. Based on our study for dynamic laser sintering process of polymer-coated molybdenum powder, its laser sintering mechanism was reported a...

2005
Leonid V. Zhigilei Dmitriy S. Ivanov

The kinetics and channels of laser energy redistribution in a target irradiated by a short, 1 ps, laser pulse is investigated in computer simulations performed with a model that combines molecular dynamics (MD) simulations with a continuum description of the laser excitation and relaxation of the conduction band electrons, based on the two-temperature model (TTM). The energy transferred from th...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1390

any change in the refractive index of a laser active medium can lead to serious degradation of beam quality, laser beam modes, laser performance and variation in the intensity distribution. alteration in the refractive index of laser active medium is especially notable in high power lasers. it is clear that in the laser beam production, the pumping agent induces a great amount of heat which...

Journal: :dental research journal 0
r. birang j. yaghini

introduction dentine hypersensitivity is a common clinical problem in dental practices. so several methods such as, nd: yag laser have been used to treat this problem. previous studies reported that nd:yag laser irradiation on root surface makes some thermal changes, like dentine melting and some other side effects which are related to power of laser irradiation. the aim of our study was to com...

2014
Xiaoqing Cao Beshah Ayalew

This paper presents a systematic control inputs optimization method for melting interface tracking in laser-aided powder deposition (LAPD) processes. Using a proposed interface approximation and a coordinate system moving with the laser source, and adopting the enhanced thermal conductivity method, the process model is first reduced to a set of coupled partial differential equations (PDEs) in f...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2015
Jesse N Clark Loren Beitra Gang Xiong David M Fritz Henrik T Lemke Diling Zhu Matthieu Chollet Garth J Williams Marc M Messerschmidt Brian Abbey Ross J Harder Alexander M Korsunsky Justin S Wark David A Reis Ian K Robinson

There is a fundamental interest in studying photoinduced dynamics in nanoparticles and nanostructures as it provides insight into their mechanical and thermal properties out of equilibrium and during phase transitions. Nanoparticles can display significantly different properties from the bulk, which is due to the interplay between their size, morphology, crystallinity, defect concentration, and...

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