The influence of the coating technique on the high cycle fatigue life of alumina coated Al 6061 alloy

Abstract

The primary objective of this study is to evaluate the influence of coating technique on the high cycle fatigue of an Al6061 alloy. Towards this purpose, Al6061 alloy fatigue samples have been coated with Al₂O₃ utilising the detonation spray, air plasma spray, micro arc oxidation and hard anodizing techniques. The high cycle fatigue life of these coated samples has been evaluated over a range of alternating stress values and compared with the fatigue life of the uncoated Al6061 alloy. It is observed that the detonation spray coated sample exhibits a higher fatigue life than the uncoated sample. In contrast, the samples coated using the other techniques exhibit poorer fatigue life compared to the uncoated sample especially at lower alternating stress values. These results have been explained on the basis of the nature of the coating-substrate interface which is strongly determined by the coating technique used to deposit the Al₂O₃ coatings.