Fretting Wear Behavior and Damage Mechanisms of Inconel X-750 Alloy in Dry Contact Condition.

Abstract

Frictional and fretting wear behaviors of Inconel X-750 alloy against GCr15 steel ball were investigated in dry contact condition with ∼60% air humidity. Fretting tests were run at the high frequency tribosystem SRV 4 in room temperature and ball-on-flat contact configuration were adopted with the relative oscillatory motion of small displacement amplitude (40 μm). Sliding regimes, wear volumes, frictional properties, and material damage mechanisms were studied with regard to different normal loading and test durations. After the tests, the worn surface morphologies were analyzed by three-dimensional (3D) optical surface profiler, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) to distinguish fretting running conditions and material responses for different test cases. It was found that the material removals by abrasive and adhesive wear, debris formation and oxidization, and wear delamination were the main damage mechanisms under the lower normal load where the full slide or gross slip regime (GSR) was dominant between the contact surfaces. On the other hand, fretting regime was found to be a stick-slip or a partial slip at greater loads where damage mechanisms were correlated with deformed asperities, fatigue cracks, and thick layer removal due to highly concentrated cyclic stresses. Time dependence was crucial during GSR where the wear volume increased substantially; however, the wear volumes and scars sizes were consistent over time because of stick-slip effects under the higher normal load.