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Insights of 3D Printing Technology with Its Types
Published in Harish Kumar Banga, Rajesh Kumar, Parveen Kalra, Rajendra M. Belokar, Additive Manufacturing with Medical Applications, 2023
Ranbir Singh Rooprai, Jaswinder Singh
Selective laser melting (SLM) is a selective laser sintering (SLS) technology that involves high-density powdered material to manufacture products. The material can be totally melted into a solid 3D component. It was invented at the Fraunhofer Institute in 1995. It is powdered 3D printing, which works by using layer-by-layer technology via CAD file or computer-based software [35,36]. It can also produce the products in order to improve high precision and low processing time surface finish. It is close to other techniques of 3D printing since it also uses CAD tools to cut processes [37,38]. It uses STL file format for fast and accurate processing and replication of pieces. Figure 2.7 gives a view of the SLM process. The powdered metal is mounted on the workplace, where the laser is used to render the process solid by intensive light. Thermal expansion, stress generation and metal changes resulting from the high heating and cooling effects of materials such as Ti-6Al-4V, TA 15 alloy and copper alloy are associated with SLM [39]. These types of defects influence the mechanical and microstructural properties of the components. For their complexity and high precision, these parts can be used in the biomedical, aerospace, automotive and other industries.
Optical Microscopy
Published in David A. Cardwell, David C. Larbalestier, Aleksander I. Braginski, Handbook of Superconductivity, 2022
Polarised light microscopy (PLM) provides information about objects in mesoscopic length scale, which is not attainable by comparable microstructure analysis techniques, such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The disadvantage of SEM is that it is not enough sensitive to anisotropy of layered cuprates (for instance it does not recognise twins, oxygen inhomogeneity and subgrains). The field observable by TEM is too small and therefore provides only very local information. The resolution limit of optical microscopy (0.2 μm) is high enough for observation of the majority of microstructural features in HTSC.
Synthesis of Oxide Dispersion Strengthened Refractory Alloys
Published in Anshuman Patra, Oxide Dispersion Strengthened Refractory Alloys, 2022
Microstructural development during the synthesis of the ODS refractory alloy has enormous importance with respect to its compact properties (green density) and later consolidated physical (density) and mechanical properties. The microstructure is generally studied using scanning electron microscopy (SEM) or transmission electron microscopy (TEM). Using TEM and an investigation provide an important insight into the location of the oxide dispersoids, the dislocation-particle interaction, and the extent of the matrix/oxide coherency. Selected area diffraction (SAD) and elemental mapping present the crystallinity and compositional analysis. Enhancement of the powder particle size of W-5%Y2O3-5%Ti after 30 h of ball milling against the initial powder particle size of W is reported by Wang et al. [13]. The paper also presents that the final structure of the ball-milled powder consists of a sphere and a sheet [13]. Synthesis of the precursor powder of W-Y2O3 through freeze-drying shows that an increase in cooling rate reduces the size of the flaky particle structure (less than 5 µm) and even the chemical composition (Figure 4.4) [14] and the addition of a polymer dispersant during freeze-drying results in a significant refinement of the grain size (mean grain size: 14 nm) [14].
Effects of the corrosion mechanism evolution of low silicon-cast aluminium alloys in service
Published in Philosophical Magazine, 2023
Tengfei Cheng, Guotong Zou, Xin Mao, Yitao Yang
The traditional measurement of grain size depends on the observation of grain boundaries in the microstructure image. Not all grain boundaries can be revealed by conventional etching methods, especially the ‘special’ grain boundaries, such as twin and small-angle grain boundaries. Because of its complexity, it is very difficult to measure the grain size of severe twin microstructures. Electron backscatter diffraction (EDSD) technology can be used to measure and analyse crystal orientation, micro-texture analysis, phase identification and grain size measurement in a large area. It can correspond to the crystal structure and orientation information with the microstructure morphology. An EBSD test can analyse the changes of grain and grain boundary in the microstructure of aluminium alloy samples exposed at different times, which can better analyse and explain the changes in microstructure and properties.
A review on parameters affecting properties of biomaterial SS 316L
Published in Australian Journal of Mechanical Engineering, 2022
Microstructure helps to study material properties such as tensile strength, grain size, porosity, impact hardness and ductility. Many researches have studied impact of cooling rate on grain size, hardness, ultimate tensile strength, secondary phase precipitates, elongation of cast part, secondary dendrite arm spacing, porosity, and yield strength. Kaiser et al., has observed that increase in cooling rate results in decrement in size and area fraction of carbides, increment in hardness, increment in mechanical properties such as tensile and yield strength and decrement in pores and ductility. They also observed that low and medium cooling rate sample reduces area fraction of pores and carbides, whereas medium and high cooling rate sample shows little difference. This change in area fraction was affected by the grain size (Kaiser et al. 2013). Ohkubo et al., concluded that mechanical properties were also affected by alloying elements. It was also observed that reduction of C, N, Si, Cr and Mo and addition of Ni, Cu, Mn, decreases the hardness and tensile strength. Main alloying elements are Ni, Mo, and Cr which mainly affect the properties of the material. Ni is an austenite stabiliser whereas Cr is ferrite stabiliser and Mo is added to provide corrosion resistance in chlorine based environment (Ohkubo et al. 1994).
Additive manufacturing of bimetallic structures
Published in Virtual and Physical Prototyping, 2022
Amit Bandyopadhyay, Yanning Zhang, Bonny Onuike
Understanding the microstructure evolution in AM processed bimetallic structures can aid the processing parameters optimisation and predict or even tailor the fabricated product’s properties. The microstructure of AM processed bimetallic structures could be significantly affected by the processing parameters and compositional variation. The microstructure variation can ultimately impact the mechanical properties of the materials. The most commonly processed AM bimetallic joint systems and extensively researched are Fe- and Ti-based alloy materials; others include Ni- and Cu-based alloys.