Influence of Process Parameters on the Microstructure, and Geometrical Characteristics of Laser Additive Manufactured (LAM) Titanium Alloy Composite Coatings

2020 ◽  
Author(s):  
O. S. Fatoba ◽  
A. M. Lasisi ◽  
S. A. Akinlabi ◽  
E. T. Akinlabi ◽  
A. A. Adediran
Keyword(s):  
Process Parameters ◽  
Laser Power ◽  
Laser Scanning ◽  
Gas Flow ◽  
Composite Coatings ◽  
Laser System ◽  
Scanning Speed ◽  
Deposition Process ◽  
Beta Phase ◽  
Influence Of Process Parameters

Abstract The study experimentally investigates the effects of Ytterbium Laser System process parameters on the resultant microstructure of Ti-6Al-4V grade 5 alloy and reinforcement powders. The deposition process was conducted employing a 3 kW (CW) Ytterbium Laser System (YLS-2000-TR) machine, coaxial to the reinforcement powder. The laser scanning speed and power were varied between the intervals of 0.8–1.0 m/min and 900–1000 W. All other parameters kept constant were the rate of gas flow, the spot diameter, and the rate of powder flow. Metallurgical studies were conducted where all the samples microstructure was characterized by employing Scanning Electron Microscopy (SEM) and Optical Microscopy (OM). The results showed that a minimum porosity was achieved at high laser power complemented with low powder feed rate. The microstructure formed was dominated by columnar grains and martensitic needle-like structures with a formation of beta phase. It was observed that the microstructure was influenced significantly by the two laser speed modes, and the laser power. The grain size and phase structure were influenced significantly by the laser power; increasing it had resulted in larger grains, and a coarser microstructure. The results also showed that the residual stresses of the optimized specimens were compressive.

Microstructural Enhancement and Performance of Additive Manufactured Titanium Alloy Grade 5 Composite Coatings

2020 ◽  
Author(s):  
O. S. Fatoba ◽  
S. A. Akinlabi ◽  
E. T. Akinlabi ◽  
L. C. Naidoo ◽  
A. A. Adediran ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Laser Scanning ◽  
Gas Flow ◽  
Composite Coatings ◽  
Laser System ◽  
Scanning Speed ◽  
Deposition Process ◽  
Traverse Speed ◽  
Industrial Applications ◽  
Grade 5

Abstract The surface integrity of Titanium alloy may be improved by surface modification, to expand its availability for more diverse industrial applications. Additive manufacturing is a commercially competitive manufacturing technique with the possibility of altering the entire perception of design and fabrication. The study experimentally investigates the effects that Ytterbium Laser System process parameters, such as laser power, powder feed rate and traverse speed, has on the resultant microstructure of Ti-6Al-4V grade 5 alloy. The deposition process was conducted employing a 3kW (CW) Ytterbium Laser System (YLS-2000-TR) machine, coaxial to the reinforcement powder. The laser scanning speed and power were varied between the intervals of 1–1.2 m/min and 900–1000 W. All other parameters kept constant were the rate of gas flow, the spot diameter, and the rate of powder flow. The microstructure was characterized by grain size and morphology by using Optical Microscopy (OM) and Scanning Electron Microscopy (SEM). During the DLMD process, the thermal histories induced in the process led to the promotion of the transformed α+β microstructure from the initial primary a microstructure; the growth and evolution of the distinct grain morphologies and stability of the alpha and beta structures upon increased and reduced structures. It was ascertained that by increasing the traverse speeds, the cooling rates increased, which resulted in the decrease in the width of the columnar grains.

scholarly journals Influence of Rapid Solidification and Optimized Process Parameters on the Microstructural Evolution of Additive Manufactured Titanium Alloy Grade 5 Composite

2021 ◽  
Vol 309 ◽  
pp. 01147
Author(s):  
O.S. Fatoba ◽  
S.A. Akinlabi ◽  
O.M. Ikumapayi ◽  
E.T. Akinlabi
Keyword(s):  
Process Parameters ◽  
Laser Scanning ◽  
Gas Flow ◽  
Laser System ◽  
Scanning Speed ◽  
Deposition Process ◽  
Cooling Rates ◽  
Grade 5 ◽  
Direct Laser ◽  
Columnar Grains

The study experimentally investigates the effects that Ytterbium Laser System process parameters, such as laser power, powder feed rate and traverse speed, has on the resultant microstructure of Ti- 6Al-4V grade 5 alloy. The deposition process was conducted employing a 3kW (CW) Ytterbium Laser System (YLS-2000-TR) machine, coaxial to the reinforcement powder. The laser scanning speed and power were varied between the intervals of 1-1.2 m/min and 900-1000 W. All other parameters kept constant where the rate of gas flow, the spot diameter, and the rate of powder flow. The microstructure was characterized by grain size and morphology by using Optical Microscopy (OM) and Scanning Electron Microscopy (SEM). The microstructural and mechanical properties were ascertained and the relationships with the process parameters were achieved. As a result of rapid cooling, the morphological features of α and α’ are distinctive and appear acicular. The structures appear coarsened. The metallurgy of the samples identifies with a morphology of multi-scale; with the coarsened alpha structures being reduced, plate-like, discrete and finer. The alpha grains closer to the fusion zone grew epitaxially, and the ones above these are acicular and lamellar. The results also indicated that slow traverse speeds increase the scale of columnar grains, while other process parameters were kept constant. Columnar microstructures became prevalent due to the dynamic temperature gradients/spikes, and sustainable cooling rates, pertaining to fabricating direct laser deposited Ti-6Al-4V grade 5 alloy. It was ascertained that by increasing the traverse speeds, the cooling rates increased, which resulted in a decrease in the width of the columnar grains.

Influence of Process Parameters on the Mechanical Response of Various Layers Processed Using Direct Metal Laser Sintering (DMLS)

2014 ◽  
Author(s):  
S. Ahmed ◽  
H. Doak ◽  
A. Mian ◽  
R. Srinivasan
Keyword(s):  
Mechanical Properties ◽  
Process Parameters ◽  
Laser Power ◽  
Laser Scanning ◽  
Mechanical Response ◽  
Scanning Speed ◽  
Direct Metal Laser Sintering ◽  
Influence Of Process Parameters ◽  
Microstructural Morphology ◽  
Laser Scanning Speed

During the DMLS process, sintering of the top layer creates melting and heat affected zone in previously sintered layers. In this paper, we will examine the effects of any given process parameter, such as laser power and laser scanning speed, on the mechanical properties and microstructural morphology within the processed layers.

Research on Warpage of Polystyrene in Selective Laser Sintering

2010 ◽  
Vol 43 ◽  
pp. 578-582 ◽  
Author(s):  
C.Y. Wang ◽  
Q. Dong ◽  
X.X. Shen
Keyword(s):  
Layer Thickness ◽  
Process Parameters ◽  
Laser Power ◽  
Selective Laser Sintering ◽  
Scanning Speed ◽  
Laser Sintering ◽  
Main Process ◽  
Influence Of Process Parameters ◽  
Temperature Changes ◽  
Hatch Spacing

Warpage is a crucial factor to accuracy of sintering part in selective laser sintering (SLS) process. In this paper, The influence of process parameters on warpage when sintering polystyrene(PS) materials in SLS are investigated. The laser power, scanning speed, hatch spacing, layer thickness as well as temperature of powder are considered as the main process parameters. The results showed that warpage increases with the increase of hatch space. Contary to it, warpage decreases with the increase of laser power. Warpage decreases with the increase of layer thickness between 0.16~0.18mm and changes little with increase of the thickness. Warpage increases along with the increase of scanning speed but decreases when the speed is over about 2000mm/s. When the temperature changes between 82°C-86°C, warpage decreases little with the increase of temperature. But further increase of temperature leads to warpage decreasing sharply when the temperature changes between 86°C-90°C.

scholarly journals Effect of Direct Energy Deposition Process Parameters on Single-Track Deposits of Alloy 718

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 96
Author(s):  
Suhas Sreekanth ◽  
Ehsan Ghassemali ◽  
Kjell Hurtig ◽  
Shrikant Joshi ◽  
Joel Andersson
Keyword(s):  
Process Parameters ◽  
Laser Power ◽  
Scanning Speed ◽  
Deposition Process ◽  
Dendritic Morphology ◽  
Area Fraction ◽  
Grain Structure ◽  
Energy Conditions ◽  
Alloy 718 ◽  
Direct Energy

The effect of three important process parameters, namely laser power, scanning speed and laser stand-off distance on the deposit geometry, microstructure and segregation characteristics in direct energy deposited alloy 718 specimens has been studied. Laser power and laser stand-off distance were found to notably affect the width and depth of the deposit, while the scanning speed influenced the deposit height. An increase in specific energy conditions (between 0.5 J/mm2 and 1.0 J/mm2) increased the total area of deposit yielding varied grain morphologies and precipitation behaviors which were comprehensively analyzed. A deposit comprising three distinct zones, namely the top, middle and bottom regions, categorized based on the distinct microstructural features formed on account of variation in local solidification conditions. Nb-rich eutectics preferentially segregated in the top region of the deposit (5.4–9.6% area fraction, Af) which predominantly consisted of an equiaxed grain structure, as compared to the middle (1.5–5.7% Af) and the bottom regions (2.6–4.5% Af), where columnar dendritic morphology was observed. High scan speed was more effective in reducing the area fraction of Nb-rich phases in the top and middle regions of the deposit. The <100> crystallographic direction was observed to be the preferred growth direction of columnar grains while equiaxed grains had a random orientation.

Composite Polymer Joining by Laser Combined Hybrid Laser Process

2014 ◽  
Vol 875-877 ◽  
pp. 1362-1366 ◽  
Author(s):  
Hae Woon Choi ◽  
Jin Young Yoon
Keyword(s):  
Laser Power ◽  
Laser Scanning ◽  
Laser System ◽  
Scanning Speed ◽  
Cnc Machining ◽  
Maximum Speed ◽  
Scanning System ◽  
Manufacturing Cost ◽  
Polymer Joining ◽  
High Flexibility

A novel hybrid process (2D scanner + LASER + CNC machining) was used to join transparent and opaque polymers. A 30W diode laser and a 3-axis CNC machining center were combined to accommodate a 2D scanning system for high flexibility and productivity. The scanning speed, the number of repetitions and the laser power were selected as parameters for the weld test. By combining CNC and laser, the productivity and accuracy were improved and manufacturing cost decreased accordingly. The maximum speed of 1130 mm/min was achieved with minimum power of 2Watt. The developed system demonstrated the joining of transparent PC and opaque ABS polymers by using 2 dimensional laser beam motion. The air gap could be minimized by using constant force on the upper holding plate, and preheating by the first run of the laser system. The weld bead decreased at the lower laser power and the higher laser scanning speed.

A New Computationally Efficient Model for Tempering in Multi-Tracks Laser Hardening

2009 ◽  
Author(s):  
Alessandro Fortunato ◽  
Leonardo Orazi ◽  
Giovanni Tani
Keyword(s):  
Process Parameters ◽  
Laser Power ◽  
Laser Scanning ◽  
Original Model ◽  
Laser Hardening ◽  
Computationally Efficient ◽  
Laser Process ◽  
Treat All ◽  
Tempering Time ◽  
Experimental Comparisons

The bottleneck in laser hardening principally occurs when large surfaces have to be treated because this process situation leads to multi-tracks laser scanning in order to treat all the component surface. Unfortunately, multi-tracks laser trajectories generate an unwanted tempering effect that depends on the overlapping of two close trajectories. To reduce the softening effects, a simulator capable to optimize the process parameters such as laser power and speed, number and types of trajectories, could sensibly increase the applicability of the process. In this paper an original model for the tempering is presented. By introducing a tempering time factor for the martensitic transformation, the hardness reduction can be predicted according to any laser process parameters, material and geometry. Experimental comparisons will be presented to prove the accuracy of the model.

Research on Microstructure and Wear Property of 45 Steel Quenched with Different Laser Power

2020 ◽  
Vol 861 ◽  
pp. 35-40
Author(s):  
Yu Liu ◽  
Tian Hao Xu ◽  
Ying Liu ◽  
Hai Cheng Zhang ◽  
Xing Xing Li ◽  
...  
Keyword(s):  
Laser Power ◽  
Laser Scanning ◽  
Scanning Speed ◽  
Wear Volume ◽  
Wear Property ◽  
Steel Matrix ◽  
Wear Properties ◽  
Laser Scanning Speed ◽  
Friction And Wear Properties ◽  
Minimum Wear

The surface of 45 steel is quenched by CO2 laser with scanning speed 1000 mm/min and different laser power 1000W, 1200W, 1400W, 1600W and 1800W. Experiments are carried out to analyze microstructure, friction and wear properties of quenched 45 steel. The results show that the quenching layer thickness increases gradually with the increase of laser power,and the maximum value of quenching layer hardness increases first and then decreases. When the laser power is 1600W, the maximum hardness value is 883HV0.5. But when the laser power is 1800W, the hardness of quenching layer becomes to decrease. The reason is the surface of 45 steel becomes to melt. The wear volume increases first and then decreases too. When laser power is 1600W, the minimum wear volume is 0.08mm3, which is 6.4% to the wear volume of 45 steel matrix without laser quenching. Therefore, better microstructure and properties of 45 steel can be obtained when laser scanning speed is 1000mm/min and laser power is 1600W.

scholarly journals Influence of Material Property Variation on Computationally Calculated Melt Pool Temperature during Laser Melting Process

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 456 ◽  
Author(s):  
Sazzad H. Ahmed ◽  
Ahsan Mian
Keyword(s):  
Thermal Conductivity ◽  
Specific Heat ◽  
Process Parameters ◽  
Laser Power ◽  
Laser Scanning ◽  
Peak Temperature ◽  
Powder Layer ◽  
Laser Melting ◽  
Melt Pool ◽  
Melt Pool Temperature

Selective Laser Melting (SLM) is a popular additive manufacturing (AM) method where a laser beam selectively melts powder layer by layer based on the building geometry. The melt pool peak temperature during build process is an important parameter to determine build quality of a fabricated component by SLM process. The melt pool temperature depends on process parameters including laser power, scanning speed, and hatch space as well as the properties of the build material. In this paper, the sensitivity of melt pool peak temperature during the build process to temperature dependent material properties including density, specific heat, and thermal conductivity are investigated for a range of laser powers and laser scanning speeds. It is observed that the melt pool temperature is most sensitive to melt pool thermal conductivity of the processed material for a set of specific process parameters (e.g., laser power and scan speed). Variations in the other mechanical–physical properties of powder and melt pool such as density and specific heat are found to have minimal effect on melt pool temperature.

Preparation of high-oriented molybdenum thin films using DC reactive magnetronsputtering

2017 ◽  
Vol 31 (07) ◽  
pp. 1750059 ◽  
Author(s):  
Zhengguo Shang ◽  
Dongling Li ◽  
She Yin ◽  
Shengqiang Wang
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Surface Roughness ◽  
Process Parameters ◽  
Gas Flow ◽  
Lattice Mismatch ◽  
Practical Significance ◽  
Process Time ◽  
Process Conditions ◽  
Influence Of Process Parameters

Since molybdenum (Mo) thin film has been used widely recently, it attracts plenty of attention, like it is a good candidate of back contact material for CuIn[Formula: see text]Ga[Formula: see text]Se[Formula: see text]S[Formula: see text] (CIGSeS) solar cells development; thanks to its more conductive and higher adhesive property. Besides, molybdenum thin film is an ideal material for aluminum nitride (AlN) thin film preparation and attributes to the tiny (−1.0%) lattice mismatch between Mo and AlN. As we know that the quality of Mo thin film is mainly dependent on process conditions, it brings a practical significance to study the influence of process parameters on Mo thin film properties. In this work, various sputtering conditions are employed to explore the feasibility of depositing a layer of molybdenum film with good quality by DC reactive magnetron sputtering. The influence of process parameters such as power, gas flow, substrate temperature and process time on the crystallinity and crystal orientation of Mo thin films is investigated. X-ray diffraction (XRD) measurements and atomic force microscope (AFM) are used to characterize the properties and surface roughness, respectively. According to comparative analysis on the results, process parameters are optimized. The full width at half maximum (FWHM) of the rocking curves of the (110) Mo is decreased to 2.7[Formula: see text], and the (110) Mo peaks reached [Formula: see text] counts. The grain size and the surface roughness have been measured as 20 Å and 3.8 nm, respectively, at 200[Formula: see text]C.

Sign in / Sign up

Export Citation Format

Share Document