Fretting Damage Behavior of NC30Fe Nickel-Based Alloy under Alternating Load Conditions

The fretting wear behavior of NC30Fe nickel-base alloy tube in contact with crossed 1Cr13 cylinderical sample has been investigated on the improved PLINT fretting rig under alternating load conditions. Different experimental conditions have been taken into consideration (i.e. environmental temperature at 25℃(air), 300℃(air) and 300℃(nitrogen), normal loads at 20 N and 50 N, tangential displacement amplitudes range from 100 μm to 200 μm, tangential fretting frequency at 2 Hz, excitation frequencies at 10 Hz and 50 Hz). Results show that the amplitudes of Mises stress for NC30Fe nickel-base alloy under the additive effect of normal exciting forces were greater than that under static loads. Consequently, the fatigue cumulative damage were obvious to be characterized and the micro-crack initiation and propagation were easier to emerge, all those led the material to peel off a lot. After cleaning, a lot of flaking pits were showed up on the worn surface according to surface morphological analysis. Fretting fatigue delamination became the main wear damage mechanism in the middle and late period of fretting wear. As the third-layer could bear, transmit and absorb the excitation energy, different layer thicknesses and degrees of oxidation can make a big difference to the results of fatigue delamination under each of the test conditions.