scholarly journals Balling Behavior of Selective Laser Melting (SLM) Magnesium Alloy

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3632
Author(s):  
Shuai Liu ◽  
Hanjie Guo
Keyword(s):  
Magnesium Alloy ◽  
Energy Density ◽  
Surface Morphology ◽  
Laser Processing ◽  
Scanning Speed ◽  
Laser Melting ◽  
Spreading Process ◽  
Metal Properties ◽  
Balling Behavior ◽  
Mg Melt

Macroscopic surface morphology and balling mechanism of AZ61 magnesium alloy prepared by Selective laser melting (SLM) have been investigated. This article studied and analyzed the surface morphology and balling phenomenon of Mg in the laser processing from the aspects of Mg inherent metal properties and laser processing. In terms of laser processing, the results show that, in the direction of increasing scanning speed, the energy density decreases, and the phenomenon of balling and porosity on the surface of the magnesium alloy is serious. When the energy density is 133.9–187.5 J/mm3, balling particles are significantly reduced. It can be seen from the low-magnification SEM image that, even at a scanning speed of 250 mm/s (Ev is 187.5 J/mm3), there are still a few small-sized balling particles on the surface. Therefore, in terms of inherent metal properties, the wettability, capillary instability, thermodynamic, and kinetic analysis of the balling behavior of Mg and other metal (Al, Fe, Cu, Ni, Ti) droplets in the SLM process has been carried out, and the dynamic model of magnesium droplet spreading/solidification was established basic on the result of experiment and metal inherent properties. The results show that SLMed magnesium alloy is a competitive process of melt diffusion and solidification. The final result depends on the intrinsic properties of the magnesium alloy and the applied laser processing parameters. The spreading process of Mg melt is very fast. Although the solidification time of Mg melts changes slowly with the increase of metal droplet temperature, the spreading speed is still very fast due to the low melt density, so the balling phenomenon of SLMed Mg can be controlled to a certain extent. Theoretically calculated, the solidification time of Mg melt droplet is longer than the wetting time at 1173 K (900 °C), so the spreading process is dominant, which can minimize the balling and realize the densification of SLMed Mg. The dynamic spreading of molten pool, the analysis of wetting and solidification process, and the establishment of SLM balling model can provide reference for the design of the SLM forming parameters of Mg and other different metals.

Track evolution and surface characteristics of selective laser melting Ti6Al4V

2018 ◽  
Vol 24 (9) ◽  
pp. 1554-1562 ◽  
Author(s):  
Luo Zhang ◽  
Haihong Zhu ◽  
Jiahe Liu ◽  
Xiaoyan Zeng
Keyword(s):  
Surface Morphology ◽  
Selective Laser Melting ◽  
Surface Characteristics ◽  
Scanning Speed ◽  
Bulk Sample ◽  
Three Dimension ◽  
Single Track ◽  
Heat Accumulation ◽  
Laser Melting ◽  
Content Type

Purpose The purpose of this paper is to investigate the track evolution and surface characteristics of selective laser melting Ti6Al4V. Design/methodology/approach In the present paper, Ti6Al4V single-track, multi-track and bulk sample were formed at different scanning speed by selective laser melting (SLM). Then, the surface morphology, three-dimension profile and surface roughness were evaluated. The width of the single and multi-track was measured and compared. Findings The results showed that the heat accumulation played a great role on the evolution of tracks and surface characteristics from single-track to multi-track and to bulk. The surface morphology of the subsequent tracks became more regular when the single-track was irregular at the same high scanning speed. The width of last track Wn was always larger than that of the first track W1. The Ra of the top of the bulk increased with the increase of the scanning speed, this trend was as same as the Ra of the single-track, but the trend of Ra of the side was opposite. Originality/value The effect of heat accumulation on the track evolution and surface characteristics is obtained. The results can help to derive a smooth surface with a regular and continuous track in SLM.

Influence of selective laser melting scanning speed parameter on the surface morphology, surface roughness, and micropores for manufactured Ti6Al4V parts

2020 ◽  
Vol 35 (15) ◽  
pp. 2025-2035
Author(s):  
Mohd Faizal Sadali ◽  
Mohamad Zaki Hassan ◽  
Fauzan Ahmad ◽  
Hafizal Yahaya ◽  
Zainudin A Rasid
Keyword(s):  
Surface Roughness ◽  
Surface Morphology ◽  
Selective Laser Melting ◽  
Scanning Speed ◽  
Laser Melting ◽  
Speed Parameter ◽  
Image Position

Abstract

Experimental Investigation into the Single-Track of Selective Laser Melting of IN625

2011 ◽  
Vol 233-235 ◽  
pp. 2844-2848 ◽  
Author(s):  
Li Wang ◽  
Qing Song Wei ◽  
Yu Sheng Shi ◽  
Jin Hui Liu ◽  
Wen Ting He
Keyword(s):  
Energy Density ◽  
Relative Density ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Laser Power ◽  
Laser Energy ◽  
Scanning Speed ◽  
Single Track ◽  
Laser Melting ◽  
Metallic Parts

Selective laser melting(SLM) is driven by the need to fabricate functional metallic parts and tools with near shape and density. The method of process to fabricate a metal part will save materials, time and energy compared to the traditional manufacturing methods. Unlike the selective laser sintering (SLS), the metal powder particles are molten by the laser beam during the process of selective laser melting. In this paper, IN625 powders were adopted to investigate the characters of single molten track. The factors that affect the surface quality and relative density are the process parameters such as the laser energy, scan speed and so on. They were studied to find out the correlation between the parameters and formation of single-track. It has been found that Optimal ratio between laser power and scanning speed (P/v) is 1-1.5 for IN625 SLM. P/v is the linear energy density. It also has been found that the width and height of single-track can be calculated when the linear energy density is given. In this study the laser power, scan spacing and the hatch spacing which affect the surface quality and the relative density of the metallic parts were optimized.

scholarly journals Investigation of the Possibility of Tailoring the Chemical Composition of the NiTi Alloy by Selective Laser Melting

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1470
Author(s):  
Evgenii Borisov ◽  
Kirill Starikov ◽  
Anatoly Popovich ◽  
Tatiana Tihonovskaya
Keyword(s):  
Energy Density ◽  
Selective Laser Melting ◽  
Laser Processing ◽  
Niti Alloy ◽  
Nickel Content ◽  
Energy Parameter ◽  
High Energy ◽  
Single Treatment ◽  
Technological Parameters ◽  
Laser Melting

In this work a study of the selective laser melting process of two NiTi alloys of equiatomic, and rich Ni composition were conducted. A study of the influence of the technological parameters on the alloy density was carried out. Values of technological parameters were obtained to ensure production of samples with the lowest number of defects. When using process parameters with the same energy density but different values of the constituent technological parameters, the amount of nickel carried away by evaporation changed insignificantly. An increase in the energy density led to an increase in the amount of nickel carried away, causing final samples with lower Ni content. When using multiple laser processing in the low-energy parameter set, it was possible to achieve a decrease in the nickel content in the alloy, similar to that with single high-energy processing. DSC studies showed a significant increase in transformation temperatures upon repeated laser processing due to the higher evaporation of nickel. The use of double laser treatment gave a decrease in the final density of the sample compared to a single treatment, but its value is still higher than when using a single treatment with a higher energy density.

scholarly journals Effect of Laser Parameters on Processing of Biodegradable Magnesium Alloy WE43 via Selective Laser Melting Method

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2623
Author(s):  
Jan Suchy ◽  
Miroslava Horynová ◽  
Lenka Klakurková ◽  
David Palousek ◽  
Daniel Koutny ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Selective Laser Melting ◽  
Laser Power ◽  
Stable Process ◽  
Scanning Speed ◽  
Process Window ◽  
Laser Melting ◽  
Weld Deposit ◽  
Thin Walls ◽  
Alloy We43

The global aim of the theme of magnesium alloy processing by the selective laser melting technology is to enable printing of replacements into the human body. By combining the advantages of WE43 magnesium alloy and additive manufacturing, it is possible to print support structures that have very similar properties to human bones. However, printing magnesium alloy parts is very difficult, and the printing strategies are still under development. Knowledge of weld deposit behaviour is needed to design a complex printing strategy and still missing. The main aim of the manuscript is the find a stable process window and identify the dependence of the weld deposit shape and properties on the laser power and scanning speed. The range of the tested parameters was 100–400 W and 100–800 mm/s for laser power and scanning speed. The profilometry and light microscopy were used to verify the continuity and shape evaluation. The microhardness and EDX analysis were used for the detailed view of the weld deposit. The manuscript specifies the weld deposit dimensions, their changes depending on laser power and scanning speed, and the continuity of the weld tracks. The stable weld deposits are made by the energy density of 5.5–12 J/mm2. Thin walls were also created by layering welds to determine the surface roughness scattering (Ra 35–60) for various settings of laser power and scanning speed.

Influence of laser parameters on the surface morphology of slurry-based Al2O3 parts produced through selective laser melting

2018 ◽  
Vol 24 (2) ◽  
pp. 333-341 ◽  
Author(s):  
Kai Zhang ◽  
Tingting Liu ◽  
Wenhe Liao ◽  
Changdong Zhang ◽  
Yishuai Yan ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Laser Power ◽  
High Performance ◽  
Thermocapillary Convection ◽  
Scanning Speed ◽  
Laser Melting ◽  
Content Type ◽  
Laser Parameters

Purpose The purpose of this paper is to obtain high-performance ceramics and enrich additive manufacturing of ceramic parts. Also, a new manufacturing technique based on slurry by selective laser melting (SLM) was studied, which has some significant advantages compared to indirect selective laser sintering of ceramic powders. Design/methodology/approach To study the effect of laser parameters on the surface morphology and melting state of pure Al2O3 ceramics, laser power varied between 100 and 200 W and scan speed varied between 60 and 90 mm/s. Findings Experimental results show that Al2O3 slurry melts completely when the laser power is about 200 W and the scanning speed is 90 mm/s. Surface quality cannot be improved effectively by changing the scanning speed. However, surface quality improves when the laser power is 200∼205 W and energy density is 889∼911 J/mm3. Thermocapillary convection was observed during SLM. By changing the temperature gradient, streak convection and flowing Bénard cells were obtained during SLM of Al2O3 slurry. Originality/value It is feasible to produce slurry ceramic parts without binders through SLM. Increasing the laser power is the most effective way to fully melt the ceramics. Complex thermocapillary convection was observed during this new process; it may be used to produce crystals.

The Surface Morphology and Electrochemical Properties of Pure Titanium Obtained by Selective Laser Melting Method

2020 ◽  
Vol 308 ◽  
pp. 21-32
Author(s):  
Anna Woźniak ◽  
Marcin Adamiak ◽  
Bogusław Ziębowicz
Keyword(s):  
Corrosion Resistance ◽  
Surface Morphology ◽  
Electrochemical Properties ◽  
Selective Laser Melting ◽  
Laser Power ◽  
Pure Titanium ◽  
Scanning Speed ◽  
Laser Melting ◽  
High Corrosion Resistance ◽  
High Corrosion

High requirements in biomedical application are associated with biocompatibility and high corrosion resistance of metal biomaterials, which are used equally in joint and bon substitution and the healing and renewal of bone weaknesses. In this paper the surface morphology and electrochemical properties of samples manufactured by Selective Laser Melting SLM method using pure titanium Grade II powder material are explored. The tested samples were produced divided into four group, depended on the values of basic process parameters – laser power P, scanning speed SP and point distance PD. The value of energy density E delivered to the sintered material was constants and was an approximately E = 75 ± 2 J/mm3. In the paper, the pitting corrosion test by recording anodic polarization curves and electrochemical spectroscopy test were carried out. Additionally the microscopic observation and microchemical analysis by SEM/EDS analysis and material density measurements were performed too. Based on the obtained results it can be concluded that the laser power P and scanning speed SP have a significant affect on the obtained full density defect free material with high corrosion resistance.

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