scholarly journals Microstructure and Microsegregation Characterization of Laser Surfaced Remelted Al-3wt%Cu Alloys

2021 ◽  
Author(s):  
Zhenjie Yao ◽  
Wenjing Ren ◽  
John Allison
Keyword(s):  
Cooling Rate ◽  
Dendrite Morphology ◽  
Melt Pool ◽  
Cu Alloy ◽  
Fine Microstructure ◽  
Equilibrium Solidification ◽  
Scan Speed ◽  
Far From Equilibrium ◽  
Beam Movement

Abstract Solidification rates during laser remelting of solid metals occur under solidification conditions that are far from equilibrium conditions. The microstructural evolution and microsegregation behaviors are affected by these conditions. This study comprised an experimental characterization of the ultra-fine microstructure and microsegregation in laser surface remelted regions of a hypoeutectic Al-Cu alloy. The laser scan speed, which controls the cooling rate within the remelted region, was observed to have a significant effect on microstructural features and microsegregation. Dendrite arm spacing was determined to decrease with increasing scan speed and depended on location within the melt pool. A transition of the dendrite morphology was also observed in the melt pools. This transition, which is attributed to the grain orientation change influenced by the laser beam movement, was experimentally characterized. The measured microsegregation profiles show decreasing microsegregation as cooling rate increases which is typically of increasing undercooling and non-equilibrium solidification.

Hypoeutectic Al–Fe Alloys: Formation and Characterization of Intermetallics by Dissolution of the Al Matrix

2019 ◽  
Author(s):  
Amauri Garcia ◽  
Pedro Goulart ◽  
Felipe Bertelli ◽  
José Spinelli ◽  
Noé Cheung
Keyword(s):  
Cooling Rate ◽  
Laser Remelting ◽  
Cooling Rates ◽  
Rich Phase ◽  
Wide Range ◽  
Equilibrium Solidification ◽  
Fe Alloys ◽  
Fe Intermetallics ◽  
Al Matrix

A careful technique of dissolution of the Al-rich phase is conducted in hypoeutectic Al–Fe alloys samples, which were solidified under a wide range of cooling rates envisaging deeper investigations on the skeletal arrangement of either Al6Fe intermetallic fibers or Al3Fe plates, and their dependence on solidification thermal parameters. The experiments were carried out with hypoeutectic Al–Fe alloys, subjected to equilibrium solidification from the melt, steady-state solidification (Bridgman growth), transient directional solidification in water-cooled and air-cooled molds and rapid solidification (laser remelting), thus permitting a significant range of microstructural scales to be examined. It is shown that Al6Fe prevails for cooling rates >1.5 K/s, and that a short zone of coexistence of Al3Fe and Al6Fe phases exists for cooling rates <1.5 K/s, which is rapidly replaced with the prevalence of Al3Fe intermetallics with further decrease in cooling rate. In contrast, even with high values of cooling rate, typical of the laser remelting process, the Al–Al3Fe eutectic is shown to prevail.

Stability and Microstructure Characterization of Barrierless Cu (Sn, C) Films

2014 ◽  
Vol 1052 ◽  
pp. 163-168 ◽  
Author(s):  
Xiao Na Li ◽  
Lu Jie Jin ◽  
Li Rong Zhao ◽  
Chuang Dong
Keyword(s):  
Diffusion Barrier ◽  
Amorphous Layer ◽  
Barrier Effect ◽  
Co Doping ◽  
Cu Alloy ◽  
Large Atom ◽  
Cu Film ◽  
Small Atom ◽  
Lower Resistivity

Thermal stability, adhesion and electronic resistivity of the Cu alloy films with diffusion barrier elements (large atom Sn and small atom C) have been studied. Ternary Cu (0.6 at.% Sn, 2 at.% C) films were prepared by magnetron co-sputtering in this work. The microstructure and resistivity analysis on the films showed that the Cu (0.6 at.% Sn, 2 at.% C) film had better adhesion with the substrate and lower resistivity (2.8 μΩ·cm, after annealing at 600 °C for 1 h). Therefore, the doping of carbon atoms makes less effect to the resistivity by decreasing the amount of the doped large atoms, which results in the decreasing of the whole resistivity of the barrierless structure. After annealing, the doped elements in the film diffused to the interface to form self-passivated amorphous layer, which could further hinder the diffusion between Cu and Si. So thus ternary Cu (0.6 at.% Sn, 2 at.% C) film had better diffusion barrier effect. Co-doping of large atoms and small atoms in the Cu film is a promising way to improve the barrierless structure.

scholarly journals Raman Spectroscopy Investigation of Graphene Oxide Reduction by Laser Scribing

2021 ◽  
Vol 7 (2) ◽  
pp. 48
Author(s):  
Vittorio Scardaci ◽  
Giuseppe Compagnini
Keyword(s):  
Raman Spectroscopy ◽  
Graphene Oxide ◽  
Reduce Graphene Oxide ◽  
Oxide Reduction ◽  
Material Parameters ◽  
Laser Scribing ◽  
Wide Range ◽  
Scan Speed ◽  
Laser Reduction

Laser scribing has been proposed as a fast and easy tool to reduce graphene oxide (GO) for a wide range of applications. Here, we investigate laser reduction of GO under a range of processing and material parameters, such as laser scan speed, number of laser passes, and material coverage. We use Raman spectroscopy for the characterization of the obtained materials. We demonstrate that laser scan speed is the most influential parameter, as a slower scan speed yields poor GO reduction. The number of laser passes is influential where the material coverage is higher, producing a significant improvement of GO reduction on a second pass. Material coverage is the least influential parameter, as it affects GO reduction only under restricted conditions.

Microstructure characterization of phase transformations in a Zn–22 wt%Al–2 wt%Cu alloy by XRD, SEM, TEM and FIM

2000 ◽  
Vol 313 (1-2) ◽  
pp. 154-160 ◽  
Author(s):  
Héctor J. Dorantes-Rosales ◽  
Vı́ctor M. López-Hirata ◽  
José L. Méndez-Velázquez ◽  
Maribel L. Saucedo-Muñoz ◽  
David Hernández-Silva
Keyword(s):  
Phase Transformations ◽  
Microstructure Characterization ◽  
Cu Alloy

Fabrication and Characterization of Targets for Shock Propagation and Radiation Burnthrough Measurements on Be-0.9 AT. % Cu Alloy

2004 ◽  
Vol 45 (2) ◽  
pp. 127-136 ◽  
Author(s):  
A. Nobile ◽  
S. C. Dropinski ◽  
J. M. Edwards ◽  
G. Rivera ◽  
R. W. Margevicius ◽  
...  
Keyword(s):  
Shock Propagation ◽  
Cu Alloy ◽  
Fabrication And Characterization

Effects of the Cooling Rate on the Acoustic Properties of Pb-10Sn Solder

2012 ◽  
Vol 729 ◽  
pp. 356-360
Author(s):  
Endre Harkai ◽  
Tamás Hurtony ◽  
Péter Gordon
Keyword(s):  
Sound Velocity ◽  
Cooling Rate ◽  
Acoustic Microscopy ◽  
Acoustic Properties ◽  
Scanning Acoustic Microscopy ◽  
Cooling Rates ◽  
Reliability Parameters ◽  
Microscopy Characterization ◽  
The Given

Microhardness and sound velocity were measured in case of differently prepared solder samples. The used Pb-10Sn solder samples were melted then cooled down applying different cooling rates. These procedures caused variant microstructure thus different microhardness and sound velocity values. The sound velocity was measured by means of scanning acoustic microscopy. Characterization of solder materials by acoustic microscopy gives the possibility to non-destructively estimate mechanical and reliability parameters of the given material.

Measurement of the Melt Pool Length During Single Scan Tracks in a Commercial Laser Powder Bed Fusion Process

2017 ◽  
Author(s):  
J. C. Heigel ◽  
B. M. Lane
Keyword(s):  
Laser Power ◽  
High Speed ◽  
Infrared Camera ◽  
Powder Bed Fusion ◽  
Single Track ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Melt Pool ◽  
Significant Difference ◽  
Scan Speed

This work presents high speed thermographic measurements of the melt pool length during single track laser scans on nickel alloy 625 substrates. Scans are made using a commercial laser powder bed fusion machine while measurements of the radiation from the surface are made using a high speed (1800 frames per second) infrared camera. The melt pool length measurement is based on the detection of the liquidus-solidus transition that is evident in the temperature profile. Seven different combinations of programmed laser power (49 W to 195 W) and scan speed (200 mm/s to 800 mm/s) are investigated and numerous replications using a variety of scan lengths (4 mm to 12 mm) are performed. Results show that the melt pool length reaches steady state within 2 mm of the start of each scan. Melt pool length increases with laser power, but its relationship with scan speed is less obvious because there is no significant difference between cases performed at the highest laser power of 195 W. Although keyholing appears to affect the anticipated trends in melt pool length, further research is required.

Characterization of cooling rate and microstructure of CuSn melt droplet in drop on demand process

2017 ◽  
Vol 27 (7) ◽  
pp. 1636-1644 ◽  
Author(s):  
Yi XU ◽  
N. ELLENDT ◽  
Xing-gang LI ◽  
V. UHLENWINKEL ◽  
U. FRITSCHING
Keyword(s):  
Cooling Rate ◽  
On Demand ◽  
Drop On Demand

scholarly journals Solidifying behavior and Characterization of Al (LM6) +SICP Metal Matrix Composites

2019 ◽  
Vol 8 (6) ◽  
pp. 2397-2403 ◽  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Cooling Rate ◽  
Metal Matrix Composite ◽  
Metal Matrix ◽  
Matrix Composites ◽  
Liquid Temperature ◽  
Step Size ◽  
Different Parts

This paper presents the investigation of moderate properties of solidified Al (LM6)+SiCp metal matrix composite (AMMC). These AMMC is fabricated by considering five different parts of casting and different weight of SiCp for reinforcement. The SiCp wt. % is varied from 5 wt. % to 15 wt. % with a step size 5 %. During casting, temperature is measured using K-thermocouple and temperature vs. solidification curve is traced. These results are compared with the solidification results of Al (LM6) alloy. It is observed that the solidifying duration of AMMC increased as well as decreased liquid temperature by adding SiCp to it. The trend of the curve is also presented that the cooling rate and the duration of solidification are different for different part of casting. Mechanical property of the each five parts of casting is tabulated. It is observed from the properties that the mechanical properties of AMMC increased by increasing the wt. % of the reinforced particles SiCp.

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