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Aluminum alloys are the predominant metal used in various industrial applications due to their lightweight, excellent corrosion resistance, high strength, and good plasticity. The aim of this work is to...

This study presents a novel synthesis route for high-entropy alloys (HEAs) and high-entropy metallic glass (HEMG) using radio frequency (RF) magnetron sputtering and controlling the HEA phase selection according to atomic size difference (δ) and film thickness. The preparation of HEAs using sputtering requires either multitargets or the preparation of a target containing at least five distinct elements. In developing HEA-preparation techniques, the emergence of a novel sputtering target system is promising to prepare a wide range of HEAs. A new HEA-preparation technique is developed to avoid multitargets and configure the target elements with the required components in a single target system. Because of a customizable target facility, initially, a TiZrNbMoTaCr target emerged with an amorphous phase owing to a high δ value of 7.6, which was followed by a solid solution (SS) by lowering the δ value to 5 (≤6.6). Thus, this system was tested for the first time to prepare TiZrNbMoTa HEA and TiZrNbMoTa HEMG via RF magnetron sputtering. Both films were analyzed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy, field emission scanning electron microscopy cross-sectional thickness, and atomic force microscopy (AFM). Furthermore, HEMG showed higher hardness 10.3 (±0.17) GPa, modulus 186 (±7) GPa, elastic deformation (0.055) and plastic deformation (0.032 GPa), smooth surface, lower corrosion current density (I corr), and robust cell viability compared to CP-Ti and HEA. XRD analysis of the film showed SS with a body-centered cubic (BCC) structure with (110) as the preferred orientation. The valence electron concentration [VEC = 4.8 (<6.87)] also confirmed the BCC structure. Furthermore, the morphology of the thin film was analyzed through AFM, revealing a smooth surface for HEMG. Inclusively, the concept of configurational entropy (ΔS mix) is applied and the crystalline phase is achieved at room temperature, optimizing the processing by avoiding further furnace usage.

High-entropy alloys (HEAs) contain more than five alloying elements in a composition range of 5–35% and with slight atomic size variation. Recent narrative studies on HEA thin films and their synthesis through deposition techniques such as sputtering have highlighted the need for determining the corrosion behaviors of such alloys used as biomaterials, for example, in implants. Coatings composed of biocompatible elements such as titanium, cobalt, chrome, nickel, and molybdenum at the nominal composition of Co30Cr20Ni20Mo20Ti10 were synthesized by means of high-vacuum radiofrequency magnetron (HVRF) sputtering. In scanning electron microscopy (SEM) analysis, the coating samples deposited with higher ion densities were thicker than those deposited with lower ion densities (thin films). The X-ray diffraction (XRD) results of the thin films heat treated at higher temperatures, i.e., 600 and 800 °C, revealed a low degree of crystallinity. In thicker coatings and samples without heat treatment, the XRD peaks were amorphous. The samples coated at lower ion densities, i.e., 20 µAcm−2, and not subjected to heat treatment yielded superior results in terms of corrosion and biocompatibility among all the samples. Heat treatment at higher temperatures led to alloy oxidation, thus compromising the corrosion property of the deposited coatings.

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