Multiscale insights into temperature effects on the sliding wear of a martensitic stainless steel

The sliding wear behavior of a high-strength martensitic stainless steel (6Cr15Mo4VN/6YC7), commonly used in high-temperature components such as control rod drive mechanisms (CRDM) in nuclear reactors, was systematically investigated at varying temperatures (room temperature, 100 °C, and 300 °C) to assess its tribological performance by multiscale characterization. The effects of temperature on wear resistance, microstructural changes, and wear mechanisms were evaluated through measurements of coefficient of friction (COF), wear rate, wear scar morphology, and oxide layer characteristics. The results show a slight decrease in hardness with increasing temperature, but a significant deterioration in wear resistance. An anomalous peak in wear rate and volume occurred at 100 °C, attributed to matrix softening and enhanced plastic deformation, with oxidative wear dominating due to severe oxide layer delamination. At room temperature, abrasive wear with surface craters was observed. At 300 °C, fatigue wear became prominent, characterized by crack formation and spalling. Oxide layers formed at all temperatures, playing a dual role as both protective barriers and sources of wear debris.