Wear resistance and microstructure of the nitriding layer formed on 2024 aluminum alloy by plasma-enhanced nitriding at different nitriding times

Influence of nitriding time on microstructure and properties of AlN nitriding layer formed on 2024 aluminum alloy by plasma-enhanced nitriding have been investigated. Nitriding process can be divided into three stages of incubation period, growth period and stable period. AlN nodules and islands were formed on the surface of aluminum alloy in incubation period. A continuous nitriding layer was formed and the nitrding layer was continuing growth with the increase of nitriding time in growth period. There is little effect on the growth of nitriding layer by prolong the nitriding time in stable period. The incubation time is calculated and the optimized nitriding time in this study is about three hours. The related mechanism is also discussed. (paper)