Comparative study of the microstructures and mechanical properties of direct laser fabricated and arc-melted AlxCoCrFeNi high entropy alloys

By Jithin Joseph, T. Jarvis, Xinhua Wu, N. Stanford, P. Hodgson, D. Fabijanic. 2015

293 citations recorded by the source corpus.

Abstract High entropy alloys (HEA) are a relatively new metal alloy system that have promising potential in high temperature applications. These multi-component alloys are typically produced by arc-melting, requiring several remelts to achieve chemical homogeneity. Direct laser fabrication (DLF) is a rapid prototyping technique, which produces complex components from alloy powder by selectively melting micron-sized powder in successive layers. However, studies of the fabrication of complex alloys from simple elemental powder blends are sparse. In this study, DLF was employed to fabricate bulk samples of three alloys based on the Al x CoCrFeNi HEA system, where x was 0.3, 0.6 and 0.85 M fraction of Al. This produced FCC, FCC/BCC and BCC crystal structures, respectively. Corresponding alloys were also produced by arc-melting, and all microstructures were characterised and compared longitudinal and transverse to the build/solidification direction by x-ray diffraction, glow discharge optical emission spectroscopy and scanning electron microscopy (EDX and EBSD). Strong similarities were observed between the single phase FCC and BCC alloys produced by both techniques, however the FCC/BCC structures differed significantly. This has been attributed to a difference in the solidification rate and thermal gradient in the melt pool between the two different techniques. Room temperature compression testing showed very similar mechanical behaviour and properties for the two different processing routes. DLF was concluded to be a successful technique to manufacture bulk HEA׳s.

Subfields: Aerospace Engineering, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/4c4c86ae7b30231b09fbe50572f22bdeb42ff000

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Citations in the corpus

Processing, alloy composition and phase transition effect on the mechanical and corrosion properties of high entropy alloys: a review (2016, background): “[38] compared the microstructure and mechanical properties of direct laser and arc-melted AlxCoCrFeNi (x = 0.”
Review of Recent Research on AlCoCrFeNi High-Entropy Alloy (2021, background): “Increasing the aluminium content in the AlxCoCrFeNi alloy increases its strength while decreasing its plasticity [64].”
Evaluation of microstructure and mechanical property variations in AlxCoCrFeNi high entropy alloys produced by a high-throughput laser deposition method (2017, background): “[11] deposited metallic powder blends of 3 compositions, and found single phase FCC at x = 0.”