نتایج جستجو برای: laser melting

تعداد نتایج: 207729  

2012
David Sands

Modification of surfaces by laser heating has become a very important aspect of modern materials science. The author’s own interests in laser processing have been involved in the main with laser processing of semiconductors, especially II-VI materials such as CdTe, but also amorphous silicon. Applications of laser processing are diverse and include, in addition to the selective recrystallisatio...

Surface roughness in the welding processes is one of the important parameters in the laser welded metal connections which affects laser beam absorption directly. When the laser beam is irradiated to the surface of the base metal, the surface roughness plays an important role in the amount of beam absorption and the amount of melting achieved and directly affects the penetration depth. The main ...

2015
Yuelin Li Zhang Jiang Xiao-Min Lin Haidan Wen Donald A. Walko Sanket A. Deshmukh Ram Subbaraman Subramanian K. R. S. Sankaranarayanan Stephen K. Gray Phay Ho

Many potential industrial, medical, and environmental applications of metal nanorods rely on the physics and resultant kinetics and dynamics of the interaction of these particles with light. We report a surprising kinetics transition in the global melting of femtosecond laser-driven gold nanorod aqueous colloidal suspension. At low laser intensity, the melting exhibits a stretched exponential k...

2015
Tobias Zier Eeuwe S. Zijlstra Alan Kalitsov Ioannis Theodonis Martin E. Garcia

Intense ultrashort laser pulses can melt crystals in less than a picosecond but, in spite of over thirty years of active research, for many materials it is not known to what extent thermal and nonthermal microscopic processes cause this ultrafast phenomenon. Here, we perform ab-initio molecular-dynamics simulations of silicon on a laser-excited potential-energy surface, exclusively revealing no...

Journal: :iJES 2015
Maximilian Drexler Dietmar Drummer Katrin Wudy

The selective laser melting of polymer powder is, for rapid prototyping applications, a well-established technology, although a lack in basic process knowledge occurs. Considering demands of series production the selective laser melting technique of polymers is faced with various challenges concerning processable material systems, process strategies and part properties. Consequently, basic rese...

2014
Y. Lawrence Yao Hongqiang Chen Wenwu Zhang

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...

2010
Rebecca A. Fischer Andrew J. Campbell

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...

2014
M. S. Ahmmed

This paper presents a numerical study of laser induced melting and solidification of crystalline Silicon (Si) using an implicit enthalpy method. The simulations are performed using the open source C++ solver known as OpenFOAM [1]. The model considers temperature dependent thermo-physical and optical properties for Si. To verify the numerical model, its predictions are compared with the experime...

H Asadi M Amin Jabbareh

Microstructural changes during laser welding and laser surface treatment has been regarded by many researchers. Most researches have focused on studying the effect of various process parameters on the size and microstructure of the heat affected zone. But some studies show that the initial microstructure of the base metal can also affect the heat affected zone dimensions and final microstructur...

2011
M. A. Montealegre

Industrial applications require parts of components with specific surface properties such are good corrosion resistance, wear resistance and hardness. Alloys with those properties are usually very expensive and there is a great interest in reducing the cost of components for fulfilling these requirements. In this sense, laser surface processing has been used as a cost-effective technique to imp...

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