A critical review of powder-based additive manufacturing of ferrous alloys: Process parameters, microstructure and mechanical properties

https://lirias.kuleuven.be/retrieve/533030

Influence of selective laser melting process parameters on texture evolution in pure copper

Laser powder bed fusion (LPBF) additive manufacturing technology is sensitive to variations in powder particle morphology and size distribution. However, the absence of a clear link between the powder characteristics and the LPBF performances complicates the development, selection and quality control of LPBF powder feedstock. In this work, three Ti-6Al-4 V powder lots produced by two different techniques, namely, plasma atomization and gas atomization, were selected and characterized. Following the micro-computed tomography analysis of the powder particles’ morphology, size and density, the flowability of these powder lots was concurrently evaluated using Hall and Gustavsson flowmeters and an FT4 powder rheometer. Using established rheology-based criteria, a figure of merit was proposed to quantify the overall powder suitability for the LPBF process. Next, the same three powder lots were used to 3D-print and post-process a series of testing specimens with different layer thicknesses and build orientations, in order to establish a correlation between the powder characteristics and the geometric and mechanical properties of a final product. This study demonstrates that the use of highly spherical powders with a limited amount of fine particles promotes their flowability and yields LPBF components with improved mechanical and geometric characteristics.

Influence of particle morphology and size distribution on the powder flowability and laser powder bed fusion manufacturability of Ti-6Al-4V alloy

Processing of Laser Materials have a variety of industrial operations in which work piece is modified by laser operation, for example, by melting it or removing material from it. In recent years, laser based technologies became important or even dominant in industrial applications such as welding, cutting or drilling. Manufacturing technology will rely on lasers and laser-based material processing for the development of new material processing methodologies and multi-functional device integration solutions. Further possibilities of processing, innovation, and advancement of laser material treatments are still in progress and very challenging. The very broad field of laser materials processing is still very fast developing. To extend this developing field of material processing, a well-organised database can give a noble guideline and great reference. That can be used as fundamentals for any research or it may help industry to choose right type of laser for specific techniques.

Laser Material Processing

The global energy infrastructure is undergoing a drastic transformation towards renewable energy, posing huge challenges on the energy materials research, development and manufacturing. Additive manufacturing has shown its promise to change the way how future energy system can be designed and delivered. It offers capability in manufacturing complex 3D structures, with near-complete design freedom and high sustainability due to minimal use of materials and toxic chemicals. Recent literatures have reported that additive manufacturing could unlock the evolution of energy materials and chemistries with unprecedented performance in the way that could never be achieved by conventional manufacturing techniques. This comprehensive review will fill the gap in communicating on recent breakthroughs in additive manufacturing for energy material and device applications. It will underpin the discoveries on what 3D functional energy structures can be created without design constraints, which bespoke energy materials could be additively manufactured with customised solutions, and how the additively manufactured devices could be integrated into energy systems. This review will also highlight emerging and important applications in energy additive manufacturing, including fuel cells, batteries, hydrogen, solar cell as well as carbon capture and storage.

Additive manufacturing : unlocking the evolution of energy materials

Selective laser melting (SLM) is one of the additive manufacturing technologies that allows for the production of parts with complex shapes from either powder feedstock or from wires. Aluminum alloys have a great potential for use in SLM especially in automotive and aerospace fields. This paper studies the influence of starting powder characteristics on the processability of SLM fabricated AlSi12 alloy. Three different batches of gas atomized powders from different manufacturers were processed by SLM. The powders differ in particle size and its distribution, morphology and chemical composition. Cubic specimens (10 mm × 10 mm × 10 mm) were fabricated by SLM from the three different powder batches using optimized process parameters. The fabrication conditions were kept similar for the three powder batches. The influence of powder characteristics on porosity and microstructure of the obtained specimens were studied in detail. The SLM samples produced from the three different powder batches do not show any significant variations in their structural aspects. However, the microstructural aspects differ and the amount of porosity in these three specimens vary significantly. It shows that both the flowability of the powder and the apparent density have an influential role on the processability of AlSi12 SLM samples.

Influence of Powder Characteristics on Processability of AlSi12 Alloy Fabricated by Selective Laser Melting

In this work the selective laser melting (SLM) of pure copper powder was studied. Because of low laser radiation absorption and high thermal conductivity it is very difficult to organize stable SLM process for copper. Five 10x10x5 mm specimens were fabricated by using different process parameters (scanning speed, point distance, exposure time, scanning strategy). The structure of fabricated specimens was studied by scanning electron microscopy of polished cross-sections. The tensile test was carried out for SLM regime with the lowest porosity.

Selective Laser Melting of Copper

Selective Laser Melting of Copper by 200 W CO2 Laser

In this research EP648 nickel base heat resistance alloy was used for Selective Laser Melting (SLM). This alloy can be used for producing details at high mechanical and thermal load by SLM for aerospace, automotive, shipbuilding and energy industries. To define the influence of SLM process parameters on EP648 4x4x4 mm cubic specimens were fabricated with different process parameters (scanning speed, laser power, layer thickness). The porosity of fabricated specimens was determined by scanning electron microscopy of polished cross-sections.

Influence of SLM Process Parameters on Porosity of Nickel Base Heat Resistance Alloy EP648

TiAl6V4 alloy is one of the widely used materials in powder bed fusion additive manufacturing technologies. In recent years selective laser melting (SLM) of TiAl6V4 alloy by fiber laser has been well studied, but SLM by CO2-lasers has not. SLM of TiAl6V4 powder by CO2-laser was studied in this paper. Nine 10×10×10 mm cubic specimens were fabricated using different SLM process parameters. All of the fabricated specimens have a good dense structure and a good surface finish quality without dimensional distortion. The lowest porosity that was achieved was about 0.5%.

https://iopscience.iop.org/article/10.1088/1757-899X/248/1/012012/pdf

P.A. Lykov

Papers

Influence of Powder Characteristics on Processability of AlSi12 Alloy Fabricated by Selective Laser Melting

Selective Laser Melting of Copper

Selective Laser Melting of Copper by 200 W CO2 Laser

Influence of SLM Process Parameters on Porosity of Nickel Base Heat Resistance Alloy EP648

Parameter optimization for selective laser melting of TiAl6V4 alloy by CO2 laser