Fretting wear mechanism of nuclear fuel cladding tube under different tangential displacement

The fretting wear behavior of Zr-1Nb alloy cladding tubes under different tangential displacement amplitudes under grid-to-rod contact conditions was investigated. The dependence of the morphology of wear scars, microstructure, and wear mechanisms on the tangential displacement amplitudes was analyzed. The results indicate that as the tangential displacement amplitude increases, the fretting regime transitions from the mixed fretting regime to the gross slip regime gradually, moreover, the coefficient of friction initially increases and then decreases, while the wear volume and maximum wear depth gradually increase. In the mixed fretting regime, the primary wear mechanism is adhesive wear, whereas the primary wear mechanism in the gross slip regime is delamination. Moreover, the extent of oxidative wear becomes more severe while the tangential displacement amplitude is larger.