Thin films of AlCrFeCoNiCu high-entropy alloy by pulsed laser deposition

Abstract

Pulsed laser deposition has been used to prepare thin films of the high entropy alloy AlCrFeCoNiCu. The 35 nm films were deposited in ultra-high vacuum onto glass at room temperature and above and analysed using X-ray diffraction and X-ray photoelectron spectroscopy. Films deposited at room temperature exhibit a mix of FCC and BCC reflections, the FCC crystallites having size similar to the film thickness, but the BCC crystallites are larger. The intensity of the reflections from both crystal structures reduce with increasing deposition temperature, the fall in BCC commencing at lower temperature than the FCC associated with a reduction of the content of Al and Cu. X-ray photoelectron spectroscopy shows that the films deposited at room temperature are closer to stoichiometry than those at higher temperatures. An important feature of the X-ray photoelectron spectroscopy depth profiles is surface segregation, the outer 3 nm of the high entropy alloy films has higher concentration of Al and, to a lesser extent, Cr. Highlights • The films exhibit mixed FCC and BCC structure. • With increasing deposition temperature, FCC and BCC reflections reduce associated with loss of Al and Cu. • Surface segregation enriches the surface of the films in Al and to a lesser extent Cr.

High‐entropy alloys and compounds for electrocatalytic energy conversion applications

“…These techniques are suitable for the formation of solid‐solution HEMs but require very high heating temperatures. The last method is gas‐phase synthesis, which includes molecular beam epitaxy, 74 atomic layer deposition, 75 and pulsed laser deposition 76 . Sophisticated and complex instruments are needed for this method, and the productivity of HEMs is not easy to promote.…”

Manufacturing Methods, Microstructural and Mechanical Properties Evolutions of High-Entropy Alloys: A Review

“…Figure 29a shows the schematic of PLD components. An intense pulsed laser beam has concentrated on the target materials whereupon the materials are vaporized into flux of fragments material, and deposited on the substrate material as thin film under the chamber either filled with background gas [86] or high vacuum atmosphere [16,87] to avoid any type of contaminations or interactions. On the other hand, PLD considers fast thin film technique (10-15 min) with high quality compared to other methods.…”

“…However, the uneven concentration of target material on the substrate occurs and hence it may not be suitable for large scale film growth. M. Cropper [16] prepared a thin film of AlCrFeCoNiCu on borosilicate glass by PLD. Results showed that large crystal sizes of both FCC and BCC phase structures were obtained at room temperature.…”

“…It is well known that a structural/tool material must possess superior properties even at a very high temperature which is the major demand for most of the modern industries. Basically, HEAs exhibits a magnificent properties such as excellent softening resistance at high temperatures [7,8], retaining the high hardness at elevated temperature [9][10][11][12], superior wear resistance [13,14] outstanding thermal stability [15], good oxidation [16,17], elevated corrosion resistance [14,18], and sluggish diffusion kinetics [19,20]. Recently, several researchers have focused their research work on HEAs.…”

Microstructure and wear resistance of the laser-cladded Al0.8CrFeCoNiCu0.5Bx high-entropy alloy coating on aluminum

“…Further, increasing the graphene oxide content improved the corrosion resistance of the coating, mainly by improving the composition segregation of the HEA. Crooper et al prepared an AlCrFeCoNiCu HEA film via pulsed laser deposition [11]. This film comprised BCC and FCC phases, with a larger crystal size of the BCC phase when compared with that of the FCC phase.…”