Effect of phase transformation on mechanical properties of Al16.80Co20.74Cr20.49Fe21.28Ni20.70 high entropy alloy coatings processed by laser cladding

Wei, X. and Zhang, P. and Yu, Z. and Yan, H. and Wu, D. and Shi, H. and Chen, J. and Lu, Q. and Tian, Y. and Ma, S. and Lei, W. (2021) Effect of phase transformation on mechanical properties of Al16.80Co20.74Cr20.49Fe21.28Ni20.70 high entropy alloy coatings processed by laser cladding. Journal of Alloys and Compounds, 862: 158563. ISSN 0925-8388

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Abstract

Eight Al16.80Co20.74Cr20.49Fe21.28Ni20.70 high entropy alloy (HEA) coatings were fabricated by laser cladding with different laser scanning speed. The mechanical properties caused by phase transformation and microstructure evolution of Al16.80Co20.74Cr20.49Fe21.28Ni20.70 HEA coatings were investigated. The experimental results showed that the volume fraction of the FCC phase and the BCC phase in each coating were different depending on laser scanning speed. High laser scanning speed will increase the number of BCC phase. BCC phase was composed of alternate A2 and B2 structure formed by spinodal decomposition. All coatings exhibited a polycrystalline structure composed of uniform equiaxed grains. The grain size of equiaxed grains reduced from 185 to 42 µm with increased laser scanning speed. The phase-mechanical properties connection at nano-scale were established by nano-hardness mapping and elastic modulus mapping. Furthermore, the micromechanical properties of individual FCC phase and BCC phase were studied by analyzing nanoindentation data statistically. The BCC phases were found to have a higher nano-hardness and elastic modulus than the FCC phases. Therefore, the increment of the BCC phase could significantly enhance the strength and wear resistance of coatings. The optimum wear resistance was obtained in V17, owning a higher volume fraction of BCC (>90%) and finer grains (75 µm). In addition, the strengthening mechanism has been discussed. Grain boundary strengthening makes a great contribution to the excellent performance of coatings. © 2020 Elsevier B.V.

Item Type:

Journal Article

Journal or Publication Title:

Journal of Alloys and Compounds

Additional Information:

This is the author’s version of a work that was accepted for publication in Journal of Alloys and Compounds. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Alloys and Compounds, 862, 2021 DOI: 10.1016/j.jallcom.2020.158563

Uncontrolled Keywords:

/dk/atira/pure/subjectarea/asjc/2500/2505

Subjects:

?? high entropy alloyslaser claddingmechanical propertiesnanoindentationmaterials chemistrymechanics of materialsmetals and alloysmechanical engineering ??

Departments:

Faculty of Science and Technology > Engineering

ID Code:

152427

Deposited By:

ep_importer_pure

Deposited On:

05 Mar 2021 12:05

Refereed?:

Yes

Published?:

Published