Page 35 - Read Online

Page 8 of 21 Chen et al. J Mater Inf 2022;2:19 https://dx.doi.org/10.20517/jmi.2022.23

Figure 5. (A) Schematic of friction stir gradient alloying (FSGA) assembly showing tapered Cu section retrofitted in the groove created
via CNC (Computer Numerical Control) milling on the base CS-HEA. The total length of the Cu section and groove is 60 mm, with at
least 16 mm of base material on either side for tool plunging and retrieval (not drawn to scale). (B) Schematic of processed (alloyed)
region after the FSGA process is completed. (C) Location of W-Re tool with respect to the tapered Cu plate during FSGA assembly and
(D) design of the tool used in the current study. (E) Schematic of LENS MR-7 system, synthesized Mo-Nb-Ta-W arrays and
corresponding HT characterization. (F, G) Design of honeycomb-structured HEAs. (A-D) Reproduced with permission [64] . Copyright
2020, Elsevier. (E) Reproduced with permission [67] . Copyright 2020, Elsevier. (F, G) Reproduced with permission [72] . Copyright 2020,
Elsevier. HEA: high-entropy alloy.

easily characterized by energy-dispersive X-ray spectroscopy (EDS) with scanning electron microscopy
(SEM) and are thus suitable for building a database with fewer compositional variables to analyze the
[66]
composition-activity relationships of HEA catalysts .

Using an Optomec LENS MR-7, the arrays of different HEA compositions were produced by HT additive
[67]
manufacturing in the form of directed energy deposition . Sample arrays of MoNbTaW HEAs were then
characterized by SEM, EDS and X-ray diffraction (XRD). All characterizations were performed
non-destructively with samples remaining on the build plate, thereby enabling future HT testing to be
performed using the same build plate, as shown in Figure 5E. Pegues et al. employed HT additive
manufacturing to synthesize a broad range of compositions in transition metal-based CoCrFeMnNi HEAs
[68]
and assessed their microstructure and hardness as a function of alloy composition . As an additive
manufacturing technique, laser metal deposition can be used to produce high-melting-point prototype