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3D Printing of Metal Matrix Composites
Published in Suneev Anil Bansal, Virat Khanna, Pallav Gupta, Metal Matrix Composites, 2023
Gurdyal Singh, Gurpreet Singh, Rajbir Bhatti, Balkar Singh
SLM has established itself as the most versatile technique due to its suitability to process a wide range of materials, including Cu-based alloys, Ti-based alloys, Fe-based alloys, Ni-based alloys, Al-based alloys, and composite, as well as amorphous materials. The microstructure and mechanical properties of a fabricated part can be tailored to suit particular applications by selecting suitable parameters such as laser parameters, hatch-style variations, internal structure heating, base-plate heating, etc. (Prashanth et al. 2015). SLM offers the advantages such as competence to process a wide variety of materials, reusability of powders, high cooling rate, flexibility in parameters selection to control the properties, relatively low cost, and ready-to-use functional parts (Ardila et al. 2014). Contrary, the SLM has some inherent limitations such as relatively slow process, part-size constraints, excessive power requirement, high initial investment, time-consuming process-parameters optimization, and rough surfaces of produced parts. Also, cracking problems sometimes occurred as is associated with brittle and high melting materials, which require substrate plate heating to control the cooling and internal stress generation. Researchers have explored the application of SLM to optimize the laser energy and scanning speed to fabricate fully dense composite parts. The results indicated a positive relationship between laser power and surface characteristics, whereas the relation with material density depends upon the reinforcement weight percentage in composite material (Han et al. 2017).
Overview of 3D-printing Technology
Published in Harish Kumar Banga, Rajesh Kumar, Parveen Kalra, Rajendra M. Belokar, Additive Manufacturing with Medical Applications, 2023
This is a powder-based fusion process that started in 1995 and uses different materials (acrylonitrile butadiene styrene (ABS), polymers, etc.). The SLM process is extensively used in distinct industry domains (automotive, medical sector, aerospace and consumer products, etc.). This method utilises a high potential density laser to heat/melt the metallic material, and the laser beam moves away from the melt pool. Finally, the molten metal is cooled, and a dense structure is developed. After that, the powder material is injected onto the surface of the previously melted layer, and the object is completed. From the view of experiment, the SLM process control is not quite simple, but from the theoretical point of view, it is very simple. The limitation of this method is that it requires supporting material, which increases the cost. In addition, post-processing is also required [50–53]. The schematic diagram of SLM is represented in Figure 15.10.
3D Printed Flexible and Stretchable Electronics
Published in Muhammad Mustafa Hussain, Nazek El-Atab, Handbook of Flexible and Stretchable Electronics, 2019
SLM is a 3D printing technology developed in the mid 1990s in Germany at Fraunhofer Institute [24]. As in SLS, SLM makes use of a high power laser to melt and weld the printing material that is usually in a powder form (Figure 14.5). One of the key features of SLM over SLS is that in SLM, the powder is completely melted to form the 3D object, while in SLS, the powder is only partially melted (sintered). For this reason, SLM can produce much higher quality objects with almost no voids in the design. Due to the high cost of SLM, it is mostly used in high-end industries such as aerospace industries where quality of the final products are more important than the production costs. For this reason, nowadays it is very difficult to find research in the area of flexible 3D printed electronics that make use of SLM as their main printing mechanism.
Precipitate formation in cerium-modified additively manufactured AlSi10Mg alloy
Published in Australian Journal of Mechanical Engineering, 2023
Vladislav Yakubov, Peidong He, Jamie J. Kruzic, Xiaopeng Li
Selective laser melting (SLM) is a popular additive manufacturing process that uses a laser to melt and fuse powder material layer by layer. As a feature of the layer-wise production, SLM provides geometric flexibility, which has spurred a revolution in part design and the development of weight optimised parts.(Emmelmann et al. 2011; Seabra 2016) Due to the high cooling rate of 103–108 K/s,(Tang et al. 2016; Li 2015; Vilaro 2010; He 2021) SLM allows components to be fabricated with unique and tailorable microstructures, leading to mechanical properties that are different than those achieved through traditional fabrication processes. This favourable attribute has enabled SLM to become a rapidly adopted manufacturing process across a wide variety of industries. However, SLM technology still presents challenges such as microstructure instability,(Maamoun et al. 2018) and only a small number of traditionally used alloys can be successfully fabricated through SLM due to inappropriate alloy compositions, leading to metallurgical defects such as cracking.(Uddin et al. 2018) Therefore, it is necessary to investigate new alloys that can be printed crack-free with near full-density while providing desirable properties such as elevated temperature mechanical properties retention.
Understanding laser-metal interaction in selective laser melting additive manufacturing through numerical modelling and simulation: a review
Published in Virtual and Physical Prototyping, 2022
Abdelkrim Bouabbou, Sebastien Vaudreuil
The intertwined powder characteristics, morphology and granulometry findings dictate the physical and the chemical behaviours of the feedstock. Packing density and flowability form the basis of powder qualification prior to SLM processing. Understanding laser powder interaction demands a strong emphasis on granulometry variations in order to ensure optimisation of the respective SLM parameters and the process as whole. Table 2 summarises some examples of the available work and their key findings on thermal properties, flowability and powder morphology and distribution. This consideration is very important because the materials used in SLM often vary in size distribution due to the process itself, something that extends to other powder characteristics (mechanical, thermal, etc.) as well as affecting final part quality.
Microstructure and properties of high power-SLM 24CrNiMoY alloy steel at different laser energy density and tempering temperature
Published in Powder Metallurgy, 2021
Miao Sun, Suiyuan Chen, Mingwei Wei, Jing Liang, Changsheng Liu, Mei Wang
In recently years, selective laser melting (SLM) is one of the rapidly developing technology of additive manufacturing (AM). It has unique advantages in manufacturing the key complex metal parts. The fabricated parts usually have fine microstructure and can be used directly without subsequent processing [1]. SLM technology has been widely used in the manufacture of titanium alloy [2], aluminium alloy [3], stainless steels [4] and nickel-based superalloy [5]. However, owing to its laser power limitation (<500 W) of most of current SLM equipment, the powder layer thickness and laser scanning speed are restricted from further improvement [6–9]. As a result, SLM technology has a bottleneck of low manufacturing efficiency when fabricating the large-scale metal parts. While the laser energy volume density is guaranteed to be constant, the laser power, scanning speed and the powder layer thickness during the deposition process can be increased, thereby increasing the processing speed of a single sample, thus improving the manufacturing efficiency of the sample. Therefore, development of high power (HP) selective laser melting technology (HP-SLM) to improve the manufacturing efficiency has become a key research direction [10].