The effect of alumina particle on improving adhesion and wear damage of wheel/rail under wet conditions

• Alumina particles obviously improve adhesion coefficient under wet condition.
• The particle parameters play a vital role in improving adhesion of wheel/rail.
• With an increase in particle size and feed rate, the damage mechanism transforms.
• The embedded particles cause high stress and the initiation and growth of cracks.

The objective of this study was to explore the effect of alumina particle on improving adhesion and wear damage of wheel/rail under wet conditions using a rolling–sliding wear apparatus. The results indicate that alumina particles significantly improve adhesion coefficient under wet conditions. The adhesion coefficient declines with the alumina particle size increasing from S (about 75 μm) to L (about 250 μm) and then keeps stable. Meanwhile, the adhesion coefficient increases firstly with the feed rate increasing from 1 to 3 g/min, and then decreases from 3 to 7 g/min, subsequently, keeps stable to 10 g/min. With an increase in particle size and feed rate, the wear rates of wheel/rail rollers increase, the thickness of plastic deformation layers and surface hardness decrease, and the damage mechanism turns from slight spalling to severe spalling and big pit. The embedded alumina particles on the roller surface produce high stress and change the plastic deformation line. Fatigue cracks develop from the surface and the wall of the pit on the rollers, and tend to connect with each other resulting in the removal of material. Furthermore, the interlayer material in the severe cracks tends to break.