Tribological and mechanical properties of surface nanocomposite AlCoCrFeNi2.1 high-entropy alloy produced by FSP

• Published in: Journal of alloys and compounds 2022-03, Vol.896, p.163052, Article 163052
• Main Authors: Mobarakeh, Seyed Ali Erfani, Seyedhosseini, Taranom, Dehghani, Kamran
• Format: Article
• Language: English
• Subjects: Diamond pyramid hardness tests; Energy dispersive X ray analysis; Eutectic high entropy alloy (EHEA); Friction stir processing; Friction stir processing (FSP); Hardness; High entropy alloys; Intermetallic phases; Mechanical properties; Microscopy; Nanocomposites; Nanoparticles; Optical microscopy; Shear properties; Shear punch test (SPT); Shear strength; Surface nanocomposite; Titanium dioxide; Tribological behavior; Tribology; Wear resistance; Wear tests; X ray analysis; X-ray fluorescence
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2021.163052

•The initial AlCoCrFeNi2.1 high entropy alloy possess eutectic structure consisting BCC/B2 phases and FCC/L12 phases.•The hardness and shear strength of the nanocomposite produced by FSP are significantly higher than that of the initial case.•After FSP, a great extent of grain refinement occurs due to the dynamic recrystallization (DRX) as well as the Zener effect.•The addition of TiO2 nanoparticles using FSP, reduces the wear resistance of high entropy alloy AlCoCrFeNi2.1. In the present work, the nanocomposite AlCoCrFeNi2.1 high-entropy alloy was produced using friction stir processing (FSP) with the addition of TiO2 nanoparticles. The size and weight percent of added nanoparticles were 30 ± 5 nm and 3 wt%, respectively. The applied rotating and transvers speeds were 800 rpm and 50 mm/min, respectively. The microstructural evolutions, the hardness changes, the shear properties and the tribological behavior 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 (EDX), X-Ray diffraction (XRD), Rockwell C and Vickers hardness testing, shear punch testing (SPT) and pin-on-disk wear test. After the FSP, the hard B2 phases, which were formed during casting, were broken and along with the TiO2 nanoparticles distributed uniformly in the matrix. These changes resulted in increase in hardness and shear strength from 301 HV to 485 HV and 332–411 MPa amounts, respectively for initial and FSPed cases; however, the wear resistance of the FSPed specimen decreased by approximately 60% compared to the initial condition.