scholarly journals Experimental and Simulation Analysis of Effects of Laser Bending on Microstructures Applied to Advanced Metallic Alloys

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 362
Author(s):  
Esteban Ramos-Moore ◽  
Joaquín Hoffmann ◽  
Rafael H. M. Siqueira ◽  
Sheila Medeiros de Carvalho ◽  
Milton S. Fernandes de Lima ◽  
...  
Keyword(s):  
Laser Beam ◽  
Simulation Analysis ◽  
High Surface ◽  
Optical Emission ◽  
High Strength ◽  
Material Behavior ◽  
Interstitial Free ◽  
Scanning Velocity ◽  
Laser Beam Scanning ◽  
Bending Angles

The aim of this work is the analysis of laser beam forming (LBF) in the bending of two relevant materials used in the transportation industry—interstitial-free (IF) steel and AA6013 high-strength aluminum alloy. Our experiments and numerical simulations consider two different operating scenarios achieved by varying the laser beam scanning velocity using linear paths. The material behavior during this process is described via a coupled thermomechanical-plasticity-based formulation that allows prediction of temperature profiles and bending angles. Metallography, glow discharge optical emission spectroscopy, and X-ray diffraction are used for microstructure characterization. In addition, microstress analyses are performed in order to study the stress behavior of the irradiated zones. It is found that LBF mainly induces grain growth and melting in the case of high surface temperatures. Before melting, the materials developed compressive stresses that could be useful in preventing cracking failures. The resulting bending angles are predicted and experimentally validated, indicating the robustness of the model to estimate LBF effects on advanced alloys. The present analysis relating bending angles together with temperature and microstructure profiles along the thickness of the sheets is the main original contribution of this work, highlighting the need for further modeling refinement of the effects of LBF on advanced alloys to include more microstructural properties, such as grain boundary diffusion and surface roughness.

scholarly journals Influence of Microstructure and Chemical Composition on Microhardness and Wear Properties of Laser Borided Monel 400

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5757
Author(s):  
Mateusz Kukliński ◽  
Aneta Bartkowska ◽  
Damian Przestacki ◽  
Grzegorz Kinal
Keyword(s):  
Wear Resistance ◽  
Laser Beam ◽  
Wear Test ◽  
Beam Power ◽  
Iron Particles ◽  
Wear Properties ◽  
Beam Scanning ◽  
Scanning Velocity ◽  
Monel 400 ◽  
Laser Beam Scanning

In this study, wear properties of Monel 400 after laser alloying with boron are described. Surfaces were prepared by covering them with boron paste layers of two different thicknesses (100 µm and 200 μm) and re-melting using diode laser. Laser beam power density was equal to 178.3 kW/cm2. Two laser beam scanning velocities were chosen for the process: 5 m/min and 50 m/min. Surfaces alloyed with boron were investigated in terms of wear resistance, and the surface of untreated Monel 400 was examined for comparison. Wear tests were performed using counterspecimen made from steel 100Cr6 and water as a lubricant. Both quantitative and qualitative analysis of surfaces after wear test are described in this paper. Additionally, microstructures and properties of obtained laser alloyed surfaces are presented. It was found that the wear resistance increased from four to tens of times, depending on parameters of the laser boriding process. The wear mechanism was mainly adhesive for surfaces alloyed with initial boron layer 100 µm thick and evolves to abrasive with increasing boron content and laser beam scanning velocity. Iron particles detached from counterspecimens were detected on each borided surface after the wear test, and it was found that the harder the surface the less built-ups are present. Moreover, adhered iron particles oxidized during the wear test.

scholarly journals An Evaluation of the use of Laser-Vibration Melting to Increase the Surface Roughness of Metal Objects

2015 ◽  
Vol 60 (1) ◽  
pp. 33-39 ◽  
Author(s):  
B. Grabas
Keyword(s):  
Surface Roughness ◽  
Laser Beam ◽  
Laser Power ◽  
Surface Structures ◽  
Scanning Velocity ◽  
New Approach ◽  
Practical Applications ◽  
Microscopic Evaluation ◽  
Heating Surfaces ◽  
Laser Beam Scanning

Abstract This paper presents preliminary, experimental results of a new, hybrid method of increasing the surface roughness of metal objects. In this new approach, metal objects are melted with a mobile laser beam while they are being rotated. A vibration generator provides circular vibrations with an amplitude of 3 mm, and the vibration plane is perpendicular to the moving laser beam. The melting tests were performed using flat carbon steel samples at a predetermined frequency of circular vibrations. The effects of laser power and laser beam scanning velocity on the melted shapes were studied. All laser melting procedures were performed at a vibration frequency of 105 Hz. The melted samples were subjected to microscopic evaluation and the Ra parameter, which characterises mean roughness, was measured using a profilometer. Melting metal samples with physically smooth surfaces (Ra = 0.21 µm) resulted in surface structures of varied roughness values, with Ra ranging from 5 µm to approximately 58 µm. The studies were undertaken to employ this technology for the purpose of passive heat exchange intensification of heating surfaces in practical applications.

scholarly journals Laser Alloying Monel 400 with Amorphous Boron to Obtain Hard Coatings

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3494 ◽  
Author(s):  
Mateusz Kuklinski ◽  
Aneta Bartkowska ◽  
Damian Przestacki
Keyword(s):  
Laser Beam ◽  
Dendritic Structure ◽  
Hard Coatings ◽  
Beam Power ◽  
Beam Scanning ◽  
Scanning Velocity ◽  
Heat Treated ◽  
Laser Beam Power ◽  
Monel 400 ◽  
Laser Beam Scanning

In this study, Monel 400 is laser heat treated and laser alloyed with boron using diode laser to obtain adequate remelting and to improve the microhardness Single laser tracks were produced on the surface with three different laser beam scanning velocities: 5, 25, and 75 m/min. In order to enrich Monel 400 with boron surfaces were covered with initial layers of two different thicknesses before the process: 100 μm and 200 μm. In all experiments, laser beam power density was equal to 178 kW/cm2. Produced laser tracks were investigated in areas of microstructure, depth of remelting and microhardness. It was found that remelted zones are mainly composed of dendrites and the more boron is present in the laser track, the dendritic structure more fragmented is. Depth of remelting and microhardness depend not only on the laser beam scanning velocity but also on thickness of the initial boron layer. While microhardness of Monel 400 is equal to approximately 160 HV0.1, microhardness up to 980 HV0.1 was obtained in areas laser alloyed with boron.

Impact of the Parameters of Laser-Vibration Treatment on the Roughness of Aluminium Melts

2014 ◽  
Vol 874 ◽  
pp. 71-75 ◽  
Author(s):  
Bogusław Grabas
Keyword(s):  
Laser Beam ◽  
Vibration Frequency ◽  
Laser Power ◽  
Experimental Results ◽  
Beam Scanning ◽  
Scanning Velocity ◽  
Vibration Treatment ◽  
The Mean ◽  
Laser Beam Scanning

This paper presents the preliminary, experimental results of laser-vibration treatment to increase the roughness of aluminium melts in compliance with EN AW-6060 (AlMgSi0.5). Using this method, metal objects are melted with a mobile laser beam while being vibrated. The effects of laser beam scanning velocity on the shapes of aluminium melts were studied at the set laser power and vibration frequency. The studied parameter was the mean roughness Ra. The value of Ra parameter grew significantly. The studies were undertaken to employ this technology for the purpose of intensifying the exchange of heat in aluminium heating panels.

Experimental investigation on resistance spot welding of dissimilar weld joints

2020 ◽  
pp. 095440892096835
Author(s):  
Rohit Verma ◽  
Kanwer Singh Arora ◽  
Lochan Sharma ◽  
Rahul Chhibber
Keyword(s):  
Welding Process ◽  
High Strength ◽  
Dynamic Resistance ◽  
Interstitial Free ◽  
Resistance Spot ◽  
Dissimilar Weld ◽  
Steel Sheets ◽  
Weld Joints ◽  
Resistance Spot Weld ◽  
Weld Current

In the present study, galvanized High Strength Interstitial Free (HIF) steel sheets, and Dual Phase (DP780) steel sheets were used for the investigations. Resistance spot weld joints were fabricated between dissimilar steel sheets. The variation in dynamic resistance (DR) with the change in welding process parameters such as weld current, weld time and electrode force were used for establishing the range of adequate weld nugget formation parameters. Effect of these parameters over tensile strength, nugget diameter and the observed failure mode was studied using one factor at a time (OFAT) approach. Microstructure and hardness of parent metal, fusion & HAZ region has also been studied.

scholarly journals High-Q MEMS Resonators for Laser Beam Scanning Displays

Micromachines ◽  
2012 ◽  
Vol 3 (2) ◽  
pp. 509-528 ◽  
Author(s):  
Ulrich Hofmann ◽  
Joachim Janes ◽  
Hans-Joachim Quenzer
Keyword(s):  
Laser Beam ◽  
Beam Scanning ◽  
High Q ◽  
Mems Resonators ◽  
Laser Beam Scanning

scholarly journals Application of Commercial Surface Pretreatments on the Formation of Cerium Conversion Coating (CeCC) over High-Strength Aluminum Alloys 2024-T3 and 7075-T6

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 930
Author(s):  
Juan Jesús Alba-Galvín ◽  
Leandro González-Rovira ◽  
Francisco Javier Botana ◽  
Maria Lekka ◽  
Francesco Andreatta ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Salt Spray ◽  
Aluminum Matrix ◽  
Optical Emission ◽  
High Strength ◽  
Chemical Conversion ◽  
Conversion Coating ◽  
Neutral Salt ◽  
Corrosion Properties ◽  
Surface Pretreatment

The selection of appropriate surface pretreatments is one of the pending issues for the industrial application of cerium-based chemical conversion coatings (CeCC) as an alternative for toxic chromate conversion coating (CrCC). A two-step surface pretreatment based on commercial products has been successfully used here to obtain CeCC on AA2024-T3 and AA7075-T6. Specimens processed for 1 to 15 min in solutions containing CeCl3 and H2O2 have been studied by scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX), glow discharge optical emission spectroscopy (GDOES), potentiodynamic linear polarization (LP), electrochemical impedance spectroscopy (EIS), and neutral salt spray (NSS) tests. SEM-EDX showed that CeCC was firstly observed as deposits, followed by a general coverage of the surface with the formation of cracks where the coating was getting thicker. GDOES confirmed an increase of the CeCC thickness as the deposition proceed, the formation of CeCC over 7075 being faster than over 2024. There was a Ce-rich layer in both alloys and an aluminum oxide/hydroxide layer on 7075 between the upper Ce-rich layer and the aluminum matrix. According to LP and EIS, CeCC in all samples offered cathodic protection and comparable degradation in chloride-containing media. Finally, the NSS test corroborated the anti-corrosion properties of the CeCC obtained after the commercial pretreatments employed.

scholarly journals Mechanical Properties of Hybrid Graphene Nanoplatelet-Nanosilica Filled Unidirectional Basalt Fibre Composites

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1468
Author(s):  
Ummu Raihanah Hashim ◽  
Aidah Jumahat ◽  
Mohammad Jawaid
Keyword(s):  
Mechanical Properties ◽  
Polymer Composites ◽  
Glass Fibre ◽  
Graphene Nanosheets ◽  
High Surface ◽  
High Surface Area ◽  
High Strength ◽  
Basalt Fibre ◽  
Graphene Nanoplatelet ◽  
Dispersion State

Basalt fibre (BF) is one of the most promising reinforcing natural materials for polymer composites that could replace the usage of glass fibre due to its comparable properties. The aim of adding nanofiller in polymer composites is to enhance the mechanical properties of the composites. In theory, the incorporation of high strength and stiffness nanofiller, namely graphene nanoplatelet (GNP), could create superior composite properties. However, the main challenges of incorporating this nanofiller are its poor dispersion state and aggregation in epoxy due to its high surface area and strong Van der Waals forces in between graphene sheets. In this study, we used one of the effective methods of functionalization to improve graphene’s dispersion and also introducing nanosilica filler to enhance platelets shear mechanism. The high dispersive silica nanospheres were introduced in the tactoids morphology of stacked graphene nanosheets in order to produce high shear forces during milling and exfoliate the GNP. The hybrid nanofiller modified epoxy polymers were impregnated into BF to evaluate the mechanical properties of the basalt fibre reinforced polymeric (BFRP) system under tensile, compression, flexural, and drop-weight impact tests. In response to the synergistic effect of zero-dimensional nanosilica and two-dimensional graphene nanoplatelets enhanced the mechanical properties of BFRP, especially in Basalt fibre + 0.2 wt% GNP/15 wt% NS (BF-H0.2) with the highest increment in modulus and strength to compare with unmodified BF. These findings also revealed that the incorporation of hybrid nanofiller contributed to the improvement in the mechanical properties of the composite. BF has huge potential as an alternative to the synthetic glass fibre for the fabrication of mechanical components and structures.

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