Hierarchical FeCoNiCr high entropy alloy thin films with combined high strength and excellent corrosion resistance

• DOI: 10.1016/j.matdes.2023.112049
• Publication Date: 2023-06-02T02:08:28Z
• Authors: Yu Li; Hao Luo; Wei Li; Chun Xu; Na Min
• Keywords: Equiaxed crystals; High-Entropy Alloys

A two-step temperature-controlled magnetron sputtering procedure was adopted to obtain a bilayer hierarchical Fe25.2Co25.2Ni27.4Cr22.2 high entropy alloy (HEA) thin film consisting of the external nano-lamellar layer and internal equiaxed zone, which displayed combined advantages hardness, good modulus excellent corrosion resistance. The roles heterogeneous nanostructure on mechanical behavior were revealed by nano-indentation Scanning Kelvin probe (SKP) methods. Compared substrate 304 ASS, HEA not only shows much higher nano-hardness values, but also possesses electron transfer resistance (12158 vs 4567 Ω.cm2) lower overall rate (6.28*10−4 6.84*10−3 mm·year−1). Moreover, outer (∼8.1 GPa) surface potential values (∼-261 mV) than those inter zone (∼5.9 GPa ∼−150 mV). former arises from significant grain refinement strengthening effect, while latter is attributed an obvious increase in energy chemically active areas such as boundaries triple junctions. This work demonstrates capability hierarchy adjust comprehensive performance multi-functional films, possess superior property comparable as-cast bulk alloys.