“Effect of tungsten carbide (WC) on electrochemical corrosion behavior, hardness, and microstructure of CrFeCoNi high entropy alloy”

Abstract

High-entropy alloy HEA (CrFeCoNi) was reinforced with variety of weight percentages of 5:20 wt.% WC particles. The alloy samples were mechanically prepared in a ball roll mill for 25 h by 10:1 ball to powder ratio at 180 rpm. Then WC was mixed with the prepared alloys in a high-speed ball mill for 1 h by 350 rpm under a controlled atmosphere. The mixed samples were compacted by a uniaxial press under 700 MPa and then sintered at 1200 °C for 90 min under air atmosphere. The corrosion behavior of the tested samples in 3.5 wt.% NaCl solution was investigated using electrochemical polarization measurements. The microstructure of the sintered samples with high relative density showed three phases, which were FCC matrix, W-rich carbide, and Cr-rich carbide and homogeneously distributed all over the alloy matrix. The hardness of the (CrFeCoNi)1-X (WC)X HEAs was increased gradually with the increasing of WC content from about 336.41 HV up to 632.48 HV at room temperature. The results indicated that the addition of WC improves the corrosion resistance. Especially, the 20 wt.% of WC addition remarkably enhanced the comprehensive corrosion resistance and easy passivation of (CrFeCoNi)1-X(WC)X HEAs. Also, the wear rate of 0 wt.% WC HEA is (1.70E-04) which is approximately 4.5 times higher than the wear rate of 20 wt.% WC HEA (3.81E-05); this means that wear resistance is significantly improved with the increase of WC content.