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Mooraj et al. J Mater Inf 2023;3:4 https://dx.doi.org/10.20517/jmi.2022.41 Page 27 of 45

Figure13.(A) Schematic of high-throughput fabrication and screening of combinatorial materials library and images of the printed
library of Cu-Zr-Al alloy system. This figure is quoted with permission from Yu et al. [175] , copyright 2021, Elsevier; (B) schematic of
combinatorial material library fabrication and ultrasonic screening to rapidly estimate effective processing parameters of Zr Ti Ni Cu 25
5
10
51
Al bulk metallic glass (BMG), adapted from Zhai et al. [177] ; (C) schematic illustration of materials library produced with discrete dots of
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varying compositions. This figure is quoted with permission from Tsai et al. [178] , copyright 2016, Elsevier; (D) schematic of DED
processing of Fe-Ni-Cr-Mo bulk materials library. This figure is quoted with permission from Islam et al. [180] , copyright 2021, AIP
Publishing. DED: Directed energy deposition.
to the spatial distribution and uniformity of the crystalline dendrites within the glassy matrix. The optimal
composition contained 4 at. % Al and used a remelting power of 175 W.

The rapid cooling rates induced by laser-based AM techniques can encourage the formation of amorphous
structures in additively manufactured alloys and hence offer a unique opportunity to study bulk metallic
[177]
glass (BMG) formation . Zhai et al. fabricated a library of one composition with varying processing
[177]
conditions to rapidly determine the optimal conditions to produce a defect-free BMG . The composition
used was Zr Ti Ni Cu Al . Using ultrasonic wave attenuation, they were able to rapidly determine the
51 5 10 25 9
presence of defects, pores, or crystalline grain boundaries that may affect the performance of the BMG. This
technique is schematically illustrated in Figure 13B. A laser power of 1,300 W and 600 mm/min was
determined to provide the highest fraction of amorphous material while remaining defect-free. This work
highlights the use of DED combined with ultrasonic wave attenuation to provide a non-destructive and easy
way to rapidly investigate and verify the glass-forming ability of many compositions immediately after they
are printed.

It is currently very difficult to predict the glass-forming ability (GFA) of an alloy composition. Thus, the
current exploration of BMGs requires a high-throughput investigation similar to that of HEAs. For this
reason, Tsai et al. deposited a combinatorial library of Cu-Zr-Ti to identify the composition with optimal
[178]
[178]
GFA . Figure 13C shows a schematic illustration of the construction of this library . The library was
built by depositing discrete hemispherical samples with varying Cu:Zr ratios between each row of samples.
After the initial deposition, a layer of Ti was deposited with various feed rates and simultaneously melted
onto the library. Each sample was remelted 2 more times to ensure the elements were fully melted and
incorporated into each sample.