|
چکیده
|
fatigue behavior of Al7075-T6 alloy was investigated. It has been demonstrated that a single Cr/CrN coating deposition at 300 ◦C is more efficient than both coating deposition at a lower temperature (150 ◦C) and duplex surface treatment. The latter includes coating deposition at 300 ◦C and re-heat treatment. The most increase for fretting fatigue life was around 200 % and was obtained for the lowest axial stress of 130 MPa which corresponds to high cycle fatigue regime (HCF). However, in low cycle fatigue regime (LCF), the fretting fatigue life of the coated specimens reduced significantly in comparison to the as-received samples by 60 % at most. Re-heat treatment after the Cr/CrN coating deposition at 300 ◦C improved the fretting fatigue life of samples in LCF regime by 33 % for the highest axial stress of 260 MPa. In HCF regime, however, the increase in the fretting fatigue life of re-heat treated coated samples was no more than 121 %, which was achieved for 130 MPa axial stress. This was around half of the maximum life improvement achieved for the single coated specimen at 300 ◦C.
|