Effects of Surface Treatment on Fatigue Property of A5052-H14 and A2017-T4 Aluminum Alloys

Abstract

In this study, the effect of anodization and electroless Ni–P plating on the fatigue strength of commercial A5052-H14 and A2017-T4 aluminum alloys was investigated. The coated aluminum alloys were tested using a rotary bending fatigue testing machine. Anodization led to a slight increase in the fatigue strength of the A2017-T4 alloy of approximately 10% because of the suppression of the generation of fatigue crack, and anodization with a 5-µm thickness for A5052-H14 also led to a slight increase in the fatigue strength. However, anodization with a 20-µm thickness for A5052-H14 led to reduced fatigue strength because of the pits that formed in the film. In addition, electroless Ni–P plating drastically improved the fatigue strength of the A5052-H14 alloy by suppressing the generation of fatigue crack. It also improved the fatigue strength of the A2017-T4 alloy in the high-stress region. However, the fatigue strength in the low-stress region was the same as that of the non-coated specimens. This fatigue strength should have originated from the hydrogen embrittlement by the hydrogen introduced into the specimen during the plating.

 

This Paper was Originally Published in Japanese in J. Japan Inst. Met. Mater. 84 (2020) 74–79.

Fig. 7 Relation between stress (σ) and number of cycles to failure (N) for electroless Ni–P plated specimens.