Nanocomposite AlCoCrFeNi2.1 high-entropy alloy produced by FSP

Abstract

In the present work, the nanocomposite AlCoCrFeNi2.1 high-entropy alloy was produced using friction stir processing (FSP). SiC nanoparticles were distributed on the surface via the stirring action imposed by FSP. The size and weight percent of added nanoparticles were 45–60 nm and 3wt.%, respectively. The applied rotating and transverse speeds were 800 rpm and 50 mm/min, respectively. The microstructural evolutions, the hardness changes and the shear properties were evaluated after applying FSP. These studies were carried out using X-ray fluorescence (XRF), optical microscopy, scanning electron microscopy (SEM), energy dispersive X-Ray analysis (EDS) and X-Ray diffraction (XRD). Also, the mechanical properties were investigated using Rockwell C and Vickers hardness testing as well as shear punch testing (SPT). The initial microstructure was significantly modified due to the occurrence of dynamic recrystallization as well as Zener pinning applied by nanoparticles. During the FSP, the SiC nanoparticles along with the broken B2 phases were distributed uniformly in the matrix. The microstructural changes resulted in an increase in the hardness and shear strength from 308 HV to 480 HV and 344 MPa to 407 MPa, respectively for initial and FSPed cases.

Keywords

• Eutectic high entropy alloy (EHEA)
• Friction stir processing (FSP)
• Surface nanocomposite
• Hardness
• Shear punch test (SPT)