Effects of Varying Copper Content on the Microstructure and Mechanical Properties of FeCoNiCu _x

Abstract

Five sets of high entropy alloys (HEAs) FeCoNiCu _x (x =0.5, 1.0, 1.5, 2.0, 2.5) were produced by vacuum induction smelting. The effects of Cu content on the microstructure and mechanical properties of the alloys were interrogated by X-ray diffractometer (XRD), field scanning electron microscope (FESEM) and tensile mechanical test. The result shows that the HEAs form single FCC solid solution phase. With the increase of Cu content, the diffraction peak first deviated to the right and then shifted to the left. The alloys changed from equiaxed crystal structure to refined dendritic crystal structure, as Cu content increased. A large number of Cu atoms are isolated in the inter-crystalline region. The tensile mechanical tests show that with the increase of Cu content, the ultimate tensile strength first increased and then decreased. When x is 2.0, the ultimate tensile strength reaches a maximum of 473 MPa, the percent elongation is 43.0%, and the fracture presents ductile behaviour.

Keywords

FeCoNiCu alloy / copper content / microstructure / elemental segregation / mechanical properties

References

[1] Cai Z, Wang Y, Cui X, et al. Design and Microstructure Characterization of FeCoNiAlCu High Entropy Alloy Coating by Plasma Cladding: In Comparison with Thermodynamic Calculation[J]. Surface and Coatings Technology, 2017, 330: 163-169.

[2] Chuang M, Tsai M, Tsai C, et al. Intrinsic Surface Hardening and Precipitation Kinetics of Al_0.3CrFe_1.5MnNi_0.5 Multi-Component Alloy[J]. Journal of Alloys & Compounds, 2013, 551: 12-18.

[3] Chou HP, Chang YS, Lee PH, et al. Microstructure, Thermophysical and Electrical Properties in Al_xCoCrFeNi (0≼x≼2) High Entropy Alloys[J]. Materials Science and Engineering: A, 2009, 163(3): 184-189.

[4] Paul T R, Belova I V, Murch G E. Analysis of Diffusion in High Entropy Alloys[J]. Materials Chemistry and Physics, 2018, 210: 301-308.

[5] Prasad H, Singh S, Panigrahi B B. Mechanical Activated Synthesis of Alumina Dispersed FeNiCoCrAlMn High Entropy Alloy[J]. Journal of Alloys and Compounds, 2017, 692: 720-726.

[6] Wang R, Chen W, Zhong J, et al. Experimental and Numerical Studies on the Sluggish Diffusion in Face Centered Cubic Co-Cr-Cu-Fe-Ni High Entropy Alloys[J]. Journal of Materials Science & Technology, 2018, 34(10): 1 791-1 798.

[7] Alijani F, Reihanian M, Gheisari K. Study on Phase Formation in Magnetic FeCoNiMnV High Entropy Alloy Produced by Mechanical Alloying[J]. Journal of Alloys and Compounds, 2019, 773: 623-630.

[8] Hadraba H, Chlup Z, Dlouhy A, et al. Oxide Dispersion Strengthened CoCrFeNiMn High Entropy Alloy[J]. Materials Science and Engineering: A, 2017, 689: 252-256.

[9] Jin G, Cai Z, Guan Y, et al. High Temperature Wear Performance of Laser-cladded FeNiCoAlCu High Entropy Alloy Coating[J]. Applied Surface Science, 2018, 445: 113-122.

[10] Rao J C, Ocelík V, Vainchtein D, et al. The Fcc-Bcc Crystallographic Orientation Relationship in Al_xCoCrFeNi High Entropy Alloys[J]. Materials Letters, 2016, 176: 29-32.

[11] Yeh JW, Chen S K, J. Lin S U, et al. Nanostructured High Entropy Alloys with Multiple Principal Elements: Novel Alloy Design Concepts and Oucomes[J]. Advanced Engineering Materials, 2004, 6: 299-303.

[12] Zhang Y, Jun Z Y, Lin J, et al. Solid — Solution Phase Formation Rules for Multi — component Alloys[J]. Advanced Engineering Materials, 2008, 10(6): 534-538.

[13] Kulkarni K, Chauhan G. Investigations of Quaternary Interdiffusion in a Constituent System of High Entropy Alloys[J]. AIP Advances, 2015, 5(9): 097 162

[14] Alaneme K K, Bodunrin M O, Oke S R. Processing, Alloy Composition and Phase Transition Effect on the Mechanical and Corrosion Properties of High Entropy Alloys: a Review[J]. Journal of Materials Research and Technology, 2016, 5(4): 384-393.

[15] Chen H, Kauffmann A, Gorr B, et al. Microstructure and Mechanical Properties at Elevated Temperatures of a New Al-Containing Refractory High Entropy Alloy Nb-Mo-Cr-Ti-Al[J]. Journal of Alloys and Compounds, 2016, 661: 206-215.

[16] Senkov O N, Wilks G B, Scott J M, et al. Mechanical Properties of Nb₂₅Mo₂₅Ta₂₅W₂₅ and V₂₀Nb₂₀Mo₂₀Ta₂₀W₂₀ Refractory High Entropy Alloys[J]. Inter Metallics, 2011, 19(5): 698-706.

[17] Cao C, Tong W, Bukhari S H, et al. Dynamic Tensile Deformation and Microstructural Evolution of Al_xCrMnFeCoNi High Entropy Alloys[J]. Materials Science and Engineering: A, 2019, 759(24): 648-654.

[18] Duan Y, Wen X, Zhang B, et al. Optimizing the Electromagnetic Properties of the FeCoNiAlCr_x High Entropy Alloy Powders by Composition Adjustment and Annealing Treatment[J]. Journal of Magnetism and Magnetic Materials, 2020, 497: 165 947.

[19] Yang X, Zhang Y. Prediction of High Entropy Stabilized Solid-solution in Multi-Component Alloys[J]. Materials Chemistry and Physics, 2012, 132(2–3): 233-238.

[20] Poletti M G, Battezzati L. Electronic and Thermodynamic Criteria for the Occurrence of High Entropy Alloys in Metallic Systems[J]. Acta Materialia, 2014, 75: 297-306.

[21] Liu Y, Chen M, Li X. Preparation, Microstructure and Properties of Al_xCoCrCuFeNi High Entropy Alloys and Their Composites[J]. Rare Metal, 2009, 09: 101-106.

[22] Guo N. Effects of Adding Elements on Microstructure and Properties of Multi-principal Component High Entropy Alloys[D], 2012 Qingdao: Shandong University of Science and Technology.

[23] Yang D. Dislocation and Metal Strengthening Mechanism[M], 1991 Harbin: Harbin Institute of Technology Press.

[24] Ye X P, Li Y L, Weng J D, et al. Research Status of Strengthening Mechanism of Particle Reinforced Metal Matrix Composites[J]. Materials Engineering, 2018, 46(12): 32-41.

[25] Yong W K, Seong G H, Yong H H, et al. Role of Rolling Temperature in the Precipitation Hardening Characteristics of Ti-Mo Microalloyed Hot-Rolled High Strength Steel[J]. Materials Science and Engineering: A, 2014, 615(5): 255-261.