scholarly journals Welding of Copper to Aluminium With Laser Beam Wavelength of 515 nm

2021 ◽  
Author(s):  
Karthik Mathivanan ◽  
Peter Plapper
Keyword(s):  
Solid Solution ◽  
Laser Beam ◽  
Laser Power ◽  
Solid Solution Phase ◽  
Research Focus ◽  
Mixed Composition ◽  
Ductile Phase ◽  
Laser Joining ◽  
Joint Fracture ◽  
Strong Joint

In laser joining of copper (Cu) and aluminum (Al) sheets, the Al sheet is widely chosen as the top surface for laser irradiation because of increased absorption of laser beam and lower melting temperature of Al in contrast to Cu. This research focus on welding from Cu side to Al sheet. The main objective of irradiating the laser beam from the copper side (Cu on top) is to exploit higher solubility of Al in Cu. A significantly lower laser power can be used with 515 nm laser in comparison to 1030 nm. In addition to low laser power, a stable welding is obtained with 515 nm. Because of this advantage, 515 nm is selected for the current research. By fusion of Cu and Al the two sheet metals are welded, with presence of beneficial Cu solid solution phase and Al+Al2Cu in the joint with the brittle phases intermixed between the ductile phase. Therefore the mixed composition strengthens the joint. However excessive mixing leads to formation of more detrimental phases and less ductile phases. Therefore optimum mixing must be maintained. Energy dispersive X-ray spectroscopy (EDS) analysis indicate that large amount of beneficial Cu solid solution and Al rich phases is formed in the strong joint. From the tensile shear test for a strong joint, fracture is obtained on the heat-affected zone (HAZ) of Al. Therefore the key for welding from copper side is to have optimum melt with beneficial phases like Cu and Al+ Al2Cu and the detrimental phases intermixed between the ductile phases

Facet crystallography of fractured V(2.7 wt% Si) solid solution

1994 ◽  
Vol 52 ◽  
pp. 622-623
Author(s):  
J. A. Sutliff ◽  
B. P. Bewlay ◽  
G. A. Henshall ◽  
M. J. Strum
Keyword(s):  
Solid Solution ◽  
Morphological Structure ◽  
Crystallographic Analysis ◽  
Solid Solution Alloy ◽  
Solid Solution Phase ◽  
Ductile Phase ◽  
High Temperature Alloys ◽  
Sem Micrograph ◽  
Facet Surface

V-Si binary alloys have been investigated as model high temperature alloys. Alloys with compositions between ~4 and 11 wt% Si can be fabricated as in-situ composites composed of the intermetallic V3Si phase and the V(Si) solid solution phase with a eutectic temperature of ~1870°C. The V(Si) phase is thought to be a ductile phase which provides toughness to the composite. We have previously reported on the fracture toughness of V-Si alloys.In this paper we present results on the fracture surface fractography and fracture facet crystallography of an arc-melted V(2.7 wt% Si) solid solution alloy fractured in bending. Figure 1 is a low magnification SEM micrograph of the surface of one half of a fractured bend bar. Many macroscopically flat facets can be seen and those for which crystallographic analysis was done have been labeled. Actually, the macro-facet surface as seen at higher magnification exhibits significant morphological structure, as can be observed in Figure 2 which shows detail of the facet labeled k.

Ductile-Phase Toughening in Niobium-Niobium Silicide Powder Processed Composites

1990 ◽  
Vol 194 ◽  
Author(s):  
Rama M. Nekkanti ◽  
Dennis M. Dimiduk
Keyword(s):  
Solid Solution ◽  
Volume Fraction ◽  
Plastic Behavior ◽  
Solid Solution Phase ◽  
Dramatic Improvement ◽  
Ductile Phase ◽  
Heat Treated ◽  
Powder Composites ◽  
Made In ◽  
Cleavage Failure

AbstractThe Nb-Si system offers a possibility of ductile-phase toughening of the brittle Nb5Si3 intermetallic with the terminal niobium-silicon solid solution. Powder composites have been made in which the volume fraction of the terminal Nb-Si phase is systematically varied in a matrix of Nb5Si3 in order to study the extent of toughening. The Nb-Si solid-solution phase was observed to exhibit cleavage failure under both as hot pressed and heat treated conditions, thereby limiting the toughening attained by the presence of this phase. Hot working of the composite results in a dramatic improvement in toughness because of a change in the plastic behavior and fracture mode of the terminal Nb-Si phase from brittle cleavage to a mixed mode of cleavage and ductile microvoid growth and coalescence (dimpled) fracture.

Transition alpha structure in beta-isomorphous Nb-Hf alloys

1987 ◽  
Vol 45 ◽  
pp. 232-233
Author(s):  
R.W. Carpenter ◽  
Changhai Li ◽  
David J. Smith
Keyword(s):  
Solid Solution ◽  
Solution Phase ◽  
Miscibility Gap ◽  
Large Strains ◽  
Solid Solution Phase ◽  
Two Phase ◽  
Diffuse Intensity ◽  
Metastable Form ◽  
The Matrix ◽  
Equilibrium Morphology

Binary Nb-Hf alloys exhibit a wide bcc solid solution phase field at temperatures above the Hfα→ß transition (2023K) and a two phase bcc+hcp field at lower temperatures. The β solvus exhibits a small slope above about 1500K, suggesting the possible existence of a miscibility gap. An earlier investigation showed that two morphological forms of precipitate occur during the bcc→hcp transformation. The equilibrium morphology is rod-type with axes along <113> bcc. The crystallographic habit of the rod precipitate follows the Burgers relations: {110}||{0001}, <112> || <1010>. The earlier metastable form, transition α, occurs as thin discs with {100} habit. The {100} discs induce large strains in the matrix. Selected area diffraction examination of regions ∼2 microns in diameter containing many disc precipitates showed that, a diffuse intensity distribution whose symmetry resembled the distribution of equilibrium α Bragg spots was associated with the disc precipitate.

scholarly journals Laser Superficial Fusion of Gold Nanoparticles with PEEK Polymer for Cardiovascular Application

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 971
Author(s):  
Oktawian Bialas ◽  
Mateusz Lis ◽  
Anna Woźniak ◽  
Marcin Adamiak
Keyword(s):  
Particle Size ◽  
Laser Beam ◽  
Gold Particle ◽  
Laser Power ◽  
Biomedical Application ◽  
Parameters Optimization ◽  
Size Reduction ◽  
Particle Size Reduction ◽  
Nano Gold ◽  
Gold Particle Size

This paper analyses the possibility of obtaining surface-infused nano gold particles with the polyether ether ketone (PEEK) using picosecond laser treatment. To fuse particles into polymer, the raw surface of PEEK was sputtered with 99.99% Au and micromachined by an A-355 laser device for gold particle size reduction. Biomimetic pattern and parameters optimization were key properties of the design for biomedical application. The structures were investigated by employing surface topography in the presence of micron and sub-micron features. The energy of the laser beam stating the presence of polymer bond thermalisation with remelting due to high temperature was also taken into the account. The process was suited to avoid intensive surface modification that could compromise the mechanical properties of fragile cardiovascular devices. The initial material analysis was conducted by power–depth dependence using confocal microscopy. The evaluation of gold particle size reduction was performed with scanning electron microscopy (SEM), secondary electron (SE) and quadrant backscatter electron detector (QBSD) and energy dispersive spectroscopy (EDS) analysis. The visibility of the constituted coating was checked by a commercial grade X-ray that is commonly used in hospitals. Attempts to reduce deposited gold coating to the size of Au nanoparticles (Au NPs) and to fuse them into the groove using a laser beam have been successfully completed. The relationship between the laser power and the characteristics of the particles remaining in the laser irradiation area has been established. A significant increase in quantity was achieved using laser power with a minimum power of 15 mW. The obtained results allowed for the continuation of the pilot study for augmented research and material properties analysis.

scholarly journals Laser beam calibration for wood surface colour treatment

2021 ◽  
Author(s):  
M. Jurek ◽  
R. Wagnerová
Keyword(s):  
Laser Beam ◽  
Power Control ◽  
Wood Surface ◽  
Laser Power ◽  
Production Quality ◽  
Chemical Processes ◽  
Continuous Control ◽  
Calibration System ◽  
Laser Engraving ◽  
Wood Surfaces

AbstractLaser engraving of photographs on wood surfaces is a challenging task. To optimize the outcome and production quality it is necessary to control every aspect of the laser engraving process. Most of the production machines and technologies overall are mainly focused on laser power control. However, with other systems and deeper knowledge of the wood characteristics it is possible to achieve even better quality. This paper deals with enlarging the number of achievable shades of burned wood and its optimization. A calibration system was developed to control colour shades of engraved wood with a combination of laser power and optic focus. With this approach it is possible to widen achievable palette of engraved shades by continuous control of chemical processes of laser and wood interaction. The production is divided into wood burning and wood carbonization by variation of laser beam focus.

Assessment of mechanical and biocompatible performance of ultra-large nitinol endovascular devices fabricated via a low-energy laser joining process

2021 ◽  
pp. 088532822110195
Author(s):  
Moataz Elsisy ◽  
Mahdis Shayan ◽  
Yanfei Chen ◽  
Bryan W Tillman ◽  
Catherine Go ◽  
...  
Keyword(s):  
Laser Power ◽  
In Vitro Study ◽  
Spot Size ◽  
Laser Joining ◽  
Study Results ◽  
Energy Laser ◽  
Joining Process ◽  
Endovascular Devices ◽  
Low Energy Laser

Nitinol is an excellent candidate material for developing various self-expanding endovascular devices due to its unique properties such as superelasticity, biocompatibility and shape memory effect. A low-energy laser joining technique suggests a high potential to create various large diameter Nitinol endovascular devices that contain complex geometries. The primary purpose of the study is to investigate the effects of laser joining process parameters with regard to the mechanical and biocompatible performance of Nitinol stents. Both the chemical composition and the microstructure of the laser-welded joints were evaluated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). In vitro study results on cytotoxicity demonstrated that the joining condition of 8 Hz frequency and 1 kW laser power showed the highest degree of endothelial cell viability after thermal annealing in 500°C for 30 min. Also, in vitro study results showed the highest oxygen content at 0.9 kW laser power, 8 Hz frequency, and 0.3 mm spot size after the thermal annealing. Mechanical performance test results showed that the optimal condition for the highest disconnecting force was found at 1 Hz frequency and 1 kW power with 0.6 mm spot size. Two new endovascular devices have been fabricated using the optimized laser joining parameters, which have demonstrated successful device delivery and retrieval, as well as acute biocompatibility.

Non-equilibrium Ti-Fe bulk alloys with ultra-high strength and enhanced ductility

2004 ◽  
Vol 851 ◽  
Author(s):  
Dmitri V. Louzguine-Luzgin ◽  
Larissa V. Louzguina-Luzgina ◽  
Hidemi Kato ◽  
Akihisa Inoue
Keyword(s):  
Solid Solution ◽  
Supersaturated Solid Solution ◽  
High Strength ◽  
Eutectic Structure ◽  
Solution Phase ◽  
Solid Solution Phase ◽  
Mechanical Fracture ◽  
Glassy Alloys ◽  
Fe Alloys ◽  
Bulk Alloys

ABSTRACTThe high-strength and ductile hypo-, hyper- and eutectic Ti-Fe alloys were formed in the shape of the arc-melted ingots with the dimensions of about 25–40 mm in diameter and 10–15 mm in height. The structure of the samples consists of cubic Pm 3 m TiFe and BCC Im 3 m β-Ti supersaturated solid solution phase. The arc-melted hypereutectic Ti65Fe35 alloy has a dispersed structure consisting of the primary TiFe phase and submicron-size eutectic structure. This alloy exhibits excellent mechanical properties: a Young's modulus of 149 GPa, a high mechanical fracture strength of 2.2 GPa, a 0.2 % yield strength of 1.8 GPa and 6.7 % ductility. The hard round-shaped intermetallic TiFe phase and the supersaturated β-Ti solid solution result in a high strength of the Ti65Fe35 alloy which in addition has much higher ductility compared to that of the nanostructured or glassy alloys. The reasons for the high ductility of the hypereutectic alloy are discussed.

Effects of hydrogen on the microstructure and microchemistry of Ti3Al – Nb intermetallics at high temperatures and high pressures

1996 ◽  
Vol 11 (9) ◽  
pp. 2186-2197 ◽  
Author(s):  
H. Z. Xiao ◽  
I. M. Robertson ◽  
H. K. Birnbaum
Keyword(s):  
Solid Solution ◽  
High Temperatures ◽  
High Pressures ◽  
Chemical Potential ◽  
Substitutional Solid Solution ◽  
Hydrogen Gas ◽  
Solid Solution Phase ◽  
Face Centered Cubic ◽  
Fine Grained ◽  
Surrounding Matrix

The microstructural and microchemical changes produced in a Ti–25Al–10Nb–3V–1Mo alloy (at. %) by charging at high temperatures in high pressures of hydrogen gas have been studied using transmission electron microscopy (TEM) and x-ray methods. Hydrides incorporating all of the substitutional solutes that formed during charging have a face-centered cubic (fcc) structure and exhibit either a plate or fine-grained morphology. With increasing hydrogen content, the size of the hydrides decreases and their microchemistry changes as they approach the stable binary hydride, TiH2. Rejection of substitutional solute elements from the hydride produces changes in the microchemistry, and consequently in the crystal structure, of the surrounding matrix. In alloys containing 50 at. % H, this solute redistribution results in the formation of an orthohombic substitutional solid solution phase containing increased levels of Nb. The driving force of this redistribution of solutes is the reduction in the chemical potential of the system as the amount of the most stable hydride, TiH2, forms. The hydrides reverted to a solid solution on annealing in vacuum at 1073 K, and the original microchemistry of the alloy was restored. Reversion from the hydride structure to the original α2 ordered DO19 structure proceeds via a disordered HCP phase.

scholarly journals Temperature Calibration Measurements based on Laser-Induced Phosphorescence Technique for Combustion Applications

2015 ◽  
Vol 10 (1) ◽  
Keyword(s):  
Laser Radiation ◽  
Laser Beam ◽  
Intensity Ratio ◽  
Laser Power ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Temperature Calibration ◽  
Phosphor Powder ◽  
Calibration Methods

Phosphor powder and phosphor-binder mixtures are successfully employed for temperature calibration measurements by using laser-induced phosphorescence (LIP) technique with an emphasis on higher precisions and accuracies than other non-intrusive methods. The phosphorescence intensities are used to perform these calibrations in three different strategies. The influence of laser power regular changes on particles heating and the calibration analyses is also carried out. A pulsed laser at 355 nm was used for exciting specimens of the phosphor powder as well as the phosphor-binder mixtures. The laser beam was directed onto the specimens and varied in three laser power levels (LPLs). The samples were kept in an oven with temperatures ranging from room temperature up to 1800 °C. The three strategies which are expressed in terms of non-dimensional intensity versus wavelength (NDI-W), normalised intensity (NI) and intensity ratio (IR) were used for the calibration assessments. A modified IR was compared with two different IRs. A precision of around ± (0.50-1.41)% was attained for different calibration methods. This research confirmed that these calibrations are possible using three different strategies, given high precisions and accuracies. The laser power alternations influenced the NI and do affect neither the NDI-W nor the IR curves. The laser radiation does not play any role for heating the particles of the studied powder.

scholarly journals Effect of Laser Parameters on Sequential Laser Beam Micromachining and Micro Electro-Discharge Machining

2021 ◽  
Author(s):  
Mir Akmam Noor Rashid ◽  
Tanveer Saleh ◽  
Wazed Ibne Noor ◽  
Mohamed Sultan Mohamed Ali
Keyword(s):  
Laser Beam ◽  
Laser Power ◽  
Short Circuit ◽  
Scanning Speed ◽  
Hole Drilling ◽  
Machining Time ◽  
Research Attention ◽  
Pilot Hole ◽  
Electro Discharge Machining ◽  
Input Parameters

Abstract Laser beam micromachining (LBMM) and micro electro-discharge machining (µEDM) based sequential micromachining technique, LBMM-µEDM has drawn significant research attention to utilizing the advantages of both methods, i.e. LBMM and µEDM. In this process, a pilot hole is machined by the LBMM and subsequently finishing operation of the hole is carried out by the µEDM. This paper presents an experimental investigation on the stainless steel (type SS304) to observe the effects of laser input parameters (namely laser power, scanning speed, and pulse frequency) on the performance of the finishing technique that is the µEDM in this case. The scope of the work is limited to 1-D machining, i.e. drilling micro holes. It was found that laser input parameters mainly scanning speed and power influenced the output performance of µEDM significantly. Our study suggests that if an increased scanning speed at a lower laser power is used for the pilot hole drilling by the LBMM process, it could result in significantly slower µEDM machining time. On the contrary, if the higher laser power is used with even the highest scanning speed for the pilot hole drilling, then µEDM processing time was faster than the previous case. Similarly, µEDM time was also quicker for LBMMed pilot holes machined at low laser power and slow scanning speed. Our study confirms that LBMM-µEDM based sequential machining technique reduces the machining time, tool wear and instability (in terms of short circuit count) by a margin of 2.5 x, 9 x and 40 x respectively in contrast to the pure µEDM process without compromising the quality of the holes.

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