Fatigue behavior of (graded) (Ti, Al)N-coated 1Cr11Ni2W2MoV stainless steel at high temperature

The high-cycle fatigue properties of graded (Ti, Al)N- and Ti0.7Al0.3N-coated 1Cr11Ni2W2MoV at 500 °C have been investigated using a rotating bending fatigue testing machine. The results show that fatigue strength and life of 1Cr11Ni2W2MoV stainless steel were apparently increased by the presence of Ti0.7Al0.3N coating. The fatigue life and strength was also improved to some extent by the presence of the graded coating at higher stress levels (475 MPa–525 MPa). The fracture morphologies were analyzed by SEM. It is concluded that the presence of the coatings, which were well adhered and have high compressive stress, restricted plastic deformation of the substrate, thus improved the fatigue properties of the steel.