Fabrication and Characterization of AlxCoFeNiCu1−x High Entropy Alloys by Laser Metal Deposition

Xueyang Chen,Sreekar Karnati,Lei Yan,Yunlu Zhang,Frank Liou

doi:10.3390/coatings7040047

Xueyang Chen, Sreekar Karnati + Show 3 more

Open Access

https://doi.org/10.3390/coatings7040047

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Journal: Coatings	Publication Date: Mar 25, 2017
Citations: 27	License type: CC BY 4.0

Affiliation: Missouri University of Science and Technology

Abstract

High entropy alloys are multicomponent alloys that have at least five different principal elements as alloying elements. Each of these elements has an atomic percentage between 5% and 35%. Typically, they form body-centered cubic (bcc) or face-centered cubic (fcc) structure and are known to possess excellent mechanical properties, corrosion resistance, excellent electric and magnetic properties. Owing to their excellent corrosion and wear resistance, researchers are focusing on employing these materials as coatings. In this research, Laser Metal Deposition (LMD) was used to fabricate AlxCoFeNiCu1−x (x = 0.25, 0.5, 0.75) high entropy alloys from elemental powder based feedstocks. Thin wall claddings fabricated via LMD were characterized by a variety of techniques. Data from X-ray Diffraction (XRD) and Electron Back Scatter Diffraction (EBSD) suggested that with increase in Al content and decrease in Cu content, a change in crystal structure from a predominantly fcc to a combined fcc and bcc structure can be observed. The microstructure of the material was observed to be columnar dendritic. Data from standard less EDS analysis showed that the dendritic phase was Fe and Co enriched while the matrix was Cu and Al enriched in all the considered high entropy alloy fabrications. The Vickers hardness data was used to estimate the mechanical properties of these deposits. Results also showed that with the increase in aluminum content, AlxCoFeNiCu1−x displayed higher hardness. The high hardness values imply potential applications in wear resistant coatings.

Highlights

High entropy alloys are novel material systems that exhibit properties much more superior than traditional alloys [1]
It has been proven that high entropy alloys are capable of excellent mechanical [2,3], electrical, and, magnetic properties [4]
Elemental powders of aluminum, cobalt, iron, nickel and copper were used as precursor materials

Summary

Introduction

High entropy alloys are novel material systems that exhibit properties much more superior than traditional alloys [1]. The high entropy alloys are made up of at least five different principal elements. These elements have similar atomic size and each element has an atomic composition between. It has been proven that high entropy alloys are capable of excellent mechanical [2,3], electrical, and, magnetic properties [4]. They are known to have excellent wear resistance [3], corrosion resistance [2,5] and thermal stability [6]

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