Fretting wear behaviors of Cr-coated Zr–1Nb alloy cladding tube mated with Zr-4 alloy dimple under different tangential displacements

The fretting wear behaviors and wear mechanism of the Cr-coated Zr–1Nb alloy cladding tube mated with Zr-4 alloy dimple were investigated under different tangential displacements. With the increasing tangential displacement, the fretting running status changes from mixed fretting regime to gross slip regime, the friction coefficient increases first and then decreases, and the removed material volume, maximum wear depth, and wear coefficient of the Cr-coated Zr–1Nb alloy cladding tube increase. Fouvry's criteria were used to verify the correctness of the fretting running status. The primary wear mechanisms in the mixed fretting regime are adhesive wear and oxidative wear, while those in the gross slip regime are delamination wear and oxidative wear. The wear mechanism of the dimple is mainly delamination wear. Cr coating inhibits the wear of the cladding tube. After the coating is completely removed, the volume of material removed from the cladding tube increases dramatically, eventually exceeding the volume of material removed by dimple. •Tangential displacement can change the abrasion mechanism of a Cr-coated Zr–1Nb alloy cladding tube.•The wear mechanism of MFR is adhesive wear and oxidative wear.•The wear mechanism of GSR is delamination wear and oxidation wear.•The coefficient of friction first increases and then decreases with the increase of tangential displacement.