Abstract
Additive manufacturing (AM) opens up the possibility of a direct build-up of components with sophisticated internal features or overhangs that are difficult to manufacture by a single conventional method. As a cost-efficient, tool-free, and digital approach to manufacturing components with complex geometries, AM of metals offers many critical benefits to various sectors such as aerospace, medical, automotive, and energy compared to conventional manufacturing processes. Direct laser fabrication (DLF) uses pre-alloyed powder mix or in-situ alloying of the elemental powders for metal additive manufacturing with excellent chemical homogeneity. It, therefore, shows great promise to enable the production of complex engineering components. This technique allows the highest build rates of the AM techniques with no restrictions on deposit size/shape and the fabrication of graded and hybrid materials by simultaneously feeding different filler materials. The advantages and disadvantages of DLF on the fabrication of compositionally complex metallic alloys are discussed in the chapter.
TopIntroduction
Additive Manufacturing (AM) was defined by ASTM (American Society for Testing & Materials) as “the process of making parts by joining materials layer-by-layer from a 3D-CAD model (ASTM: F2792-12a)” (Sugavaneswaran & Arumaikkannu, 2014). The process of fabricating objects by the in-situ melting followed by the rapid solidification of a powder layer has created a new scientific frontier in physical metallurgy for the fabrication of compositionally complex alloy components with excellent strength-ductility synergy (Joseph et al., 2015). This process opens up new technological opportunities for the manufacturers to directly build-up of parts with sophisticated internal features or overhangs that are difficult to manufacture by a single conventional method. The ASTM 52900:2015 classifies various AM processes into following categories (Bandyopadhyay & Heer, 2018; Tofail et al., 2018) such as Material/Binder jetting; Laser engineered net shaping (LENS)/ direct laser fabrication (DLF); Material extrusion; Vat photopolymerization; Selective laser melting (SLM) and; Sheet lamination.
As a cost-efficient, tool-free and digital approach to manufacturing components with complex geometries, AM of metals offer vital benefits to aerospace, medical, automotive, and energy sectors compared to traditional manufacturing processes (Bourell, 2016; Conner et al., 2014a). It includes the reduced fabrication time and cost, material waste and enables low-volume production of complicated part designs with minimal geometric constraints and a high degree of customization (Conner et al., 2014b). Parts can be compact and multi-functional with the elimination of joints and fewer assembled components, leads to the savings of production/assembly lead time, cost and environmental impact (Berdine, DiPaola, & Weinberg, 2019; Bogers, Hadar, & Bilberg, 2016; Fera, Macchiaroli, Fruggiero, & Lambiase, 2018). The researchers of Monash University (in association with Deakin University and CSIRO, Australia), fabricated world’s first AM printed jet engine with a significantly reduced number of components and was on display at Paris Airshow-2015 (Figure 1 (Wu, 2015)). A well-known practical example of such compact design is the 3D-printed (SLM) fuel nozzle of the LEAP jet engine with a compact design (GE Aviation-2016, one component instead of 18) with sophisticated cooling pathways and support ligaments (Kellens et al., 2017). This light and cost-effective engine resulted in improved fuel efficiency and durability of the aircraft.
Key Terms in this Chapter
MCAM: The Monash Centre for Additive Manufacturing (MCAM) is a strategic research centre of Monash University, Australia. The centre takes fundamental research from material science, alloy design and processing, surface engineering, corrosion and hybrid materials.
High-Throughput: High throughput technology refers to the efficient processing/analysis of large numbers of samples and variables for further developments.
ASTM: American Society for Testing and Materials (ASTM) provides additive Manufacturing Technology standards define terminology, measure the performance of different production processes, ensure the quality of the end products, and specify procedures for the calibration of additive manufacturing machines.
HEA: High entropy alloys (HEA) are a new class of alloys introduced in 2004. These alloys have four or more alloying elements in equiatomic or near-equiatomic ratio and form solid solution structures.
Optomec: Optomec Inc. is a US-based firm who is a leading manufacturer of next-generation advanced DLF Processing for Industrial Metal Additive Manufacturing.
Functionally-Graded Materials: Functionally-Graded Materials (FGMs) exhibit mutually exclusive properties for multiple functions and may be achieved by varying the chemical composition across the component or by surface modification. For example, the gears should be tough enough inside to withstand the fracture and should also be hard on the outside to resist wear.
Trumpf: Trumpf Group is a German industrial machine manufacturing company and a leading manufacturer of laser systems and 3D printing machines for metal components.