Tribological Behavior of Boronized Fe40Mn20Cr20Ni20 High-Entropy Alloys

Abstract

The tribological behavior of hot-rolled and boronized Fe40Mn20Cr20Ni20 high-entropy alloys (HEAs) sliding against a Si3N4 ball was investigated in the air, deionized water and seawater. The results showed that the hot-rolled Fe40Mn20Cr20Ni20 HEA was composed of an FCC (face-centered cubic) phase. In addition, the boronized HEA was composed of a great number of borides, including CrB, FeB, MnB, Fe2B, Fe3B and MnB2. The hardness increased from 139 HV to 970 HV after boronizing. In air, the wear rate decreased from 4.51 × 10−4 mm3/Nm to 0.72 × 10−4 mm3/Nm after boronizing. The wear mechanism transformed from abrasive wear and oxidative wear to the polishing effect. After boronizing, in the deionized water, the wear rate decreased from 1.27 × 10−4 mm3/Nm to 8.43 × 10−5 mm3/Nm. The wear mechanism transformed from abrasive wear and delamination wear to delamination wear. In the seawater, the wear rate decreased by about ten times that of hot-rolled alloy.

Microstructure Characterization and Robust Lubrication Performance of CoCrNi Medium Entropy Alloy with Advanced Electrochemical Boronizing Treatment

“…It can be seen from Figure 11 that CoCrNi and CoCrMo MEAs have the lowest wear rate than HEAs after boronizing. [ 22,30,33 ]…”

“…It can be seen that the boronized CoCrNi MEA has the lowest wear rate about 0.16 × 10 −5 mm 3 Nm −1 under the deionized water condition, which is an order of magnitude lower than that of HEAs. [ 30,32,33 ]…”

“…Wear rate of boronized alloys under the deionized water condition, compared with the results of the previous studies. [ 30,32,33 ] …”

“…It can be seen from Figure 11 that CoCrNi and CoCrMo MEAs have the lowest wear rate than HEAs after boronizing. [22,30,33] Figure 12 shows the wear rate of boronized alloys under the deionized water condition. It can be seen that the boronized CoCrNi MEA has the lowest wear rate about 0.16 Â 10 À5 mm 3 Nm À1 under the deionized water condition, which is an order of magnitude lower than that of HEAs.…”

“…The wear rate was also reduced by 80%. Guo et al [ 33 ] performed boronizing treatment on Fe 40 Mn 20 Cr 20 Ni 20 HEA and found that the wear rate decreased from 1.27 × 10 −4 to 8.43 × 10 −5 mm 3 Nm −1 under deionized water conditions. Moreover, the wear mechanism transformed from abrasive wear and delamination wear to delamination wear.…”