Microstructure, Mechanical Properties and Tribological Properties of NiAlComposites Reinforced by CrMnFeCoNiHigh-Entropy Alloy

Abstract

NiAl-based composites reinforced by CrMnFeCoNi high-entropy alloy (HEA) particles were fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). The microstructure, mechanical, and tribological properties of the NiAl-HEA composites were investigated. Microstructural analyses show that after SPS, the HEA phase homogenously distributed in the NiAl matrix. Non-uniform diffusion of various elements occurred during the high temperature sintering process. Transmission electron microscope (TEM) observation of the composites revealed that many nano particle of Al2O3 generated at the grain boundary. The yield strength significantly increased after adding HEA particles. The compressive strength of the composites increased with the contents of HEA increasing, which should be attributed to the second phase hardening effect of HEA particles and fine grain strengthening effect. The composite of 10 wt.% HEA exhibited significant room temperature compressive properties, with the ultimate compressive strength of 2692 MPa and the compressive strain of 34.2%, respectively. The results of the wear tests show that the addition of HEA will reduce the wear resistance of composites to some extent and slightly increase the coefficients of friction (COFs) of the composites.

Polymorphic Transformation and Magnetic Properties of Rapidly Solidified Fe26.7Co26.7Ni26.7Si8.9B11.0 High-Entropy Alloys

“…Even in some cases, a little intermetallic compounds precipitate in the single solid solution matrix, leading to the further enhancement of the mechanical properties of HEAs [ 3 , 5 ]. Additionally, recent studies have shown that the HEAs fabricated using different methods exhibit superior mechanical and physical properties such as high hardness, ultrahigh fracture toughness, good wear resistance, good tribological properties, excellent high temperature softening resistance, good magnetic properties, and good corrosion resistance [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. It has been claimed that these promising properties are ascribed to the high-entropy of alloys, the sluggish diffusion, the cocktail effect, and the large lattice distortion of the respective structures [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 12 , 25 , 26 , 27 ].…”