Metal Alloys for Fusion‐Based Additive Manufacturing

Abstract

Metal additive manufacturing (AM) is an innovative manufacturing technique, which builds parts incrementally layer by layer. Thus, metal AM has inherent advantages in part complexity, time, and waste saving. However, due to its complex thermal cycle and rapid solidification during processing, the alloys well suit and commercially used for metal AM today are limited. Therefore, it is important to understand the alloying strategy and current progress with materials performance to consider alloy development for metal AM. This review presents the current range of alloys available for metal AM, including titanium, steel, nickel, aluminum, less common alloys (including Mg alloys, metal matrix composites alloys, and low melting point alloys), and compositionally complex alloys (including bulk metallic glasses and high entropy alloys) with a focus on the relationship between compositions, processing, microstructures, and properties of each alloy system. In addition, some promising alloy systems for metal AM are highlighted. Approaches for designing and optimizing new materials for metal AM have been summarized.

Microstructure, Solidification Texture, and Thermal Stability of 316 L Stainless Steel Manufactured by Laser Powder Bed Fusion

“…of the cellular dendrites microstructure of 316 L steel manufactured by LPBF were consistent with previous reports [5][6][7][18][19][20][21][22]. XRD, EBSD, and TEM analysis carried out in the present investigation revealed a fully austenitic structure in the LPBF 316 L steel.…”

“…Not all newly nucleated colonies had the same color as the adjacent grains in the substrate, meaning that that not all substrate grains satisfied the conditions for epitaxial nucleation. Similar epitaxial nucleation between the layers was observed by EBSD in different AM materials [5][6][7]25,26]. Figure 2c also shows that in many colonies, the orientation in the inner region was generally the same.…”

Aging Response of an A357 Al Alloy Processed by Selective Laser Melting

“…As expected for cubic crystals, previous studies showed that grains with <001> parallel to the building direction, and therefore parallel to the maximum thermal gradient, favorably grow to the detriment of adjacent grains . At higher magnifications, as previously reported for different Al–Si systems processed by SLM, the microstructure of the as built alloy reveals primary α ‐Al cells decorated at boundaries by tiny eutectic Si particles (Figure a) . The SEM image depicted in Figure b shows that the microstructure slightly changes nearby the melt pool boundaries.…”

Fatigue behaviour of laser powder bed fusion (L-PBF) Ti–6Al–4V, Al–Si–Mg and stainless steels: a brief overview

“…However, machined or turned samples almost doubles the fatigue strength, as a reduction of roughness value from 13 to 1 lm (Uhlmann et al 2017), Table 8. Similar improvement in fatigue strength of 316L steel for machined and polished samples has been reported in many studies (Riemer et al 2014;Spierings et al 2011;Zhang et al 2018a). Hence, L-PBF 316L and PH steel show comparable results with their conventional counterparts only after machining, as shown in Fig.…”