مشخصات پژوهش

The wear behavior of high entropy alloys is of great importance due to their use in harsh operating conditions in applications such as marine, chemical processing and energy production. For this reason, this study aims to investigate the tribological performance of Co-free FeNiMnCrTiAl high entropy alloy in dry sliding, seawater and H2SO4 (0.5 M and 0.005 M) environments. Wear tests according to ASTM G133 standard were performed against Al2O3 ball at 2.5 N, 5 N and 10 N loads, 2 Hz reciprocating frequency, 5 mm stroke and 20 mm/s sliding speed for 100 m sliding distance. The microstructure of the high entropy alloy produced by casting, homogenization and hot rolling consists of simple face-centered cubic (FCC) and Cr2Al phases. Key findings demonstrate that the alloy exhibits significantly superior wear resistance in corrosive environments compared to dry sliding, with the wear resistance ranking as follows: 0.5 M H₂SO₄ > 0.5 H₂SO₄ 10−3 M > seawater > dry sliding. The enhanced performance in liquid media is attributed to tribo-chemical film formation, cooling, and effective debris removal. Distinct wear mechanisms were identified across conditions: abrasive wear dominated under low-load dry sliding, transitioning to oxidative and delamination mechanisms at higher loads. In seawater, mixed-mode wear involving delamination and tribo-oxide layer interaction was observed. Acidic environments revealed load-dependent behavior, with adhesive and plastic deformation at 2.5 N, micro-scratching at 5 N, and severe abrasive-oxidative wear at 10 N. Interestingly, surface degradation was more pronounced in the 0.005 M H₂SO₄ solution due to unstable passive film formation, despite its lower acidity. The results of this study demonstrated that the Co-free FeNiMnCrTiAl HEA exhibits significantly superior wear resistance compared to conventional single-phase FCC HEAs, highlighting its potential as a promising candidate for abrasive and corrosive environments.