Beam Feed Rate Research Articles

Laser assisted fabrication of mechanochemically robust Ti3Au intermetallic at Au-Ti interface

Intermetallics such as Ti3Au are characterised by improved mechanical properties and reduced susceptibility to corrosion. This study extensively blends the techniques of process simulation by finite element analysis, light microscopy, scanning electron microscopy, energy dispersive spectroscopy and structural roentgenography analysis to investigate the interfacial intermetallics (IMC) in Au-Ti system. Ti was electrochemically coated with a micrometric layer of gold and then laser-treated in a wide range of parameters. Variability included both the laser beam power and the beam feed rate. The experimental results confirm that the formation of an intermetallic Ti3Au phase is possible. Finite element method was employed to numerically estimate the transient temperature values at the Au-Ti interface during laser treatment. At laser power 100 W and scan speed of 1.5 mm/s, the interfacial temperature reached a magnitude larger than the melting point of Ti for a duration less than 5.0 ms. The decrease of scan speed to 1.0 mm/s for constant P, increased this duration up to 97.0 ms where both provided sufficient energy for convection-based reaction at the interface. Through nanoscale molecular dynamics simulation, it has been revealed that during nanoindentation, Ti and Au atoms of Ti3Au IMC exert alarger resistance force to the indenter as compared to the atoms of pure Ti material. The IMC material not only offers amore robust mechanical response during indentation but also exhibits superiority over pure Ti material in a corrosion test.

Thermal Annealing and Laser Treatment of Sol-gel Derived Zirconia Thin Films

Soluble precursor powders were prepared from zirconium propoxide and acetylacetone by evaporation of volatile products directly after the hydrolysis step. Dissolution of the solid residue resulted in solutions that were further processed by dip coating on glass substrates. One set of asdried films was thermally annealed in an oven at temperatures between 300 and 600°C. In parallel, samples were irradiated by a CO2 laser, in doing so laser power density and beam feed rate were varied. The thermally cured and laser treated film series were characterized with respect to film thickness, refractive index, phase content, crystallite size and film microstructure.

Generation of textured diamond abrasive tools by continuous-wave CO2 laser: Laser parameter effects and optimisation

Textured Diamond Abrasive Tools (TDATs) have been attracted multitudes of attentions from both academic scholars and industrial engineers due to the reported superior grinding performances. However, the absence of appropriate fabrication technologies can still be considered as the bottleneck of wide applications of TDATs. To fill this gap, this paper utilised the continuous-wave CO2 laser to produce passive-grinding structures on the diamond abrasive tool surfaces. Not only the theoretical analysis of the non-metallic multi-material ablation threshold for diamond abrasive tools, but also the experimental investigation of the effects of both the laser power and the beam feed rate on both the topographies and morphologies of the produced structures were studied. The different structure generation mechanisms under different laser parameters were analyzed as well. Based on this, the strategy for selecting proper ablation parameters was provided. Various examples of the produced textured wheels were given in the end to prove the study significance and feasibility. The presented work was expected helpful to provide a new method for industries to produce textured grinding wheels in an efficient and low-cost way.

1207 Mid-ultraviolet pulsed solid-state laser micromachining of SiC single crystal wafer

Mid-UV pulsed solid-state laser micromachining on SiC single crystal wafer have been investigated symmetrically. SiC single crystal wafer is used in MEMS at harsh environment. Cutting, marking and surface ablation of SiC single crystal wafer have been produced by direct writing. Laser ablation results including ablation threshold and ablation rate are discussed. The results show that ablation rate of mid-UV pulsed solid-state laser micromachining depends on several factors, including laser pulse energy, beam feed rate (cutting speed), and number of laser scan. The results indicates that the laser ablation process of SiC single crystal wafer could be a mixed of photothermal and photochemical process. The mid-UV laser micromachining process appears to be dominated by photothermal process.

Laser micromachining of the materials using in microfluidics by high precision pulsed near and mid-ultraviolet Nd:YAG lasers

Abstract Both near-ultraviolet (UV) laser and mid-UV laser micromachining on materials have been investigated systematically. The materials used in this research are sapphire, silicon, and Pyrex glass that are commonly used in microfluidic applications. Cutting, marking and surface ablation of those materials have been produced by direct writing using a high-speed x – y galvanomechanical beam positioner. Laser ablation results, including ablation rate and precision, are discussed. The results show that the both ablation rate and precision of laser micromachining depend on several factors, including focus length, beam feed rate (cutting speed), the pulse repetition rate and the absorption coefficient of the materials. The result indicates that the laser ablation process of these materials could be a mixed of photothermal and photochemical processes when using a near nanosecond pulse laser. The UV (355 nm) laser micromachining process, however, appears to be dominated by a photothermal process than those of mid-UV (266 nm) laser.

Parametric studies on pulsed near ultraviolet frequency tripled Nd:YAG laser micromachining of sapphire and silicon

The use of a near ultraviolet Nd:YAG laser for rapid micromachining of sapphire and silicon has been systematically investigated. Cutting, marking and surface ablation of both materials have been produced by direct writing using a high-speed x– y galvanomechanical beam positioner. Machining results such as ablation rate and efficiency are discussed. The results show that the quality and efficiency of the laser machining depend on several factors, including focus length, beam feed rate (cutting speed) and the pulse repetition rate. The surface morphology and ablation rate indicate that the laser ablation process of sapphire could be a mixed photothermal and photochemical process, while that of silicon appears be dominated by a photothermal process when using a near UV nanosecond pulses.