Stress-dependent nanowear of nickel-based single crystal superalloy: Transition from hillock to groove

Abstract

Nickel-based single crystal (NBSC) superalloys have been applied as a typical structural material for aero-engine blades and their wear resistance is crucial to service lifespan. Here, we demonstrated that the wear of NBSC superalloys exhibits a transition from conventional grooves to unanticipated hillocks with decreasing loads. The hillock volumetric growth was found to be linearly dependent on the sliding distance and normal load, in accordance with the Archard's wear law. The subsequent atomistic simulations reveal that the hillock formation stems from the presence of a low-density amorphous structure. These discoveries can not only provide basic insights into the wear mechanism of the NBSC superalloys but also contribute to the life expectancy of structural components at the macroscale.