Fretting fatigue failure behavior of Nickel-based single crystal superalloy dovetail specimen in contact with powder metallurgy pads at high temperature

Fretting fatigue failure behavior of DD6 Nickel-based single crystal superalloy dovetail attachment at 600 degrees C has been investigated. The contact surface material is oxidized at high temperature and the oxides are compacted on the contact surface. The contact surface is delaminated and many pits are formed, which result in stress concentration near the wear pits and promote crack initiation. All the dovetail specimens fail at the contact leading edge area and along (111) [1 (1) over bar0] and ((1) over bar1 (1) over bar) [110] slip systems, which are resulted from the large resolved shear stress at the contact edge. Crystallographic plasticity finite element method is used to obtain the contact stress and strain, and the calculated maximum damage area agrees well with the experimental results.