Abstract
This paper investigates the fatigue behaviour of aluminium alloy 7075-T6 coated with 3-μm-thick titanium nitride (TiN) coatings using a physical vapour deposition (PVD) process. Preliminary work demonstrated that the high operating temperature of the deposition process markedly reduced the tensile properties of the coating-substrate system by comparison to the uncoated Al 7075-T6. The low tensile properties of the coated material caused a considerable reduction in the load-carrying capacity under fatigue loading. Consequently, a substantial decrease of 90% was found in the fatigue life of the coated material. The lost tensile properties were then satisfactorily recovered by applying a post heat treatment to the coated alloy leading to significant fatigue life improvements to approach original properties of the uncoated Al 7075-T6. The evaluation of fatigue fracture surfaces at high magnifications indicated that the fatigue cracks initiated at the outer surface of the aluminium substrate under the coating thin layer.
Original language | English |
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Pages (from-to) | 294-302 |
Number of pages | 9 |
Journal | Materials and Design |
Volume | 39 |
DOIs | |
Publication status | Published - Aug 2012 |
Keywords
- A. Non-ferros metals and alloys
- B. Film and sheet
- E. Fatigue