Effect of Al/Ni Ratio, Heat Treatment on Phase Transformations and Microstructure of AlₓFeCoCrNi₂₋ₓ (x=0.3, 1) High Entropy Alloys

Abstract

Laser-aided direct metal deposition, an additive manufacturing technique, was successfully used to fabricate thin walled high entropy alloy components. In this study, the ratio of aluminum to nickel in the AlFeCoCrNi system was decreased to observe the transition of the solid solution from a body centered cubic to a face centered cubic structure. Aluminum concentration was found to cause ordering and spinodal decomposition concomitantly in two of the compositions. The lattice parameter increased from 0.288. nm to 0.357. nm and the hardness decreased from 670. Hv to 149. Hv respectively. Differential thermal analysis was used to track the solidification paths of each of the compositions. Annealing at high temperature led to σ phase transformation in some of the compositions which along with solid solution strengthening accounted for the high softening resistance of these alloys. The optimization of the Al/Ni ratio in these alloys for better mechanical properties has been discussed with the help of an additional alloy composition as an example.

Department(s)

Materials Science and Engineering

Second Department

Mechanical and Aerospace Engineering

Keywords and Phrases

3D Printers; Alloys; Crystal Structure; Deposition; Differential Thermal Analysis; Entropy; Heat Treatment; Intermetallics; Manufacture; Phase Transitions; Rapid Solidification; Solid Solutions; Solidification; Spinodal Decomposition; Stainless Steel; Thermoanalysis; Thin Walled Structures; Additive Manufacturing; Advanced Materials; Aluminum Concentration; Direct Metal Deposition; Face Centered Cubic Structure; High Entropy Alloys; Laser-Aided Direct Metal Depositions; Solid Solution Strengthening; Aluminum; Additive Manufacturing; Advanced Materials; High Entropy Alloysalloys

International Standard Serial Number (ISSN)

0261-3069

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2015 Elsevier, All rights reserved.

Publication Date

01 Sep 2015

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