Experimental Research On Aging Precipitation Behavior Of 6063 Aluminum Alloy

For 6000 series aluminum alloys,the effect of natural aging on artificial aging has been controversial.Under the traditional aging temperature(175?),when the alloy content is higher than lwt.%,Natural aging(NA)will inhibit the peak hardness of the artificial aging(AA)of the alloy(negative effect).However,when the alloy content is less than 1 wt.%,Natural aging will increase the peak hardness of the artificial aging alloy.But for alloys with alloy content higher than lwt.%,High temperature will reverse the negative effect of natural aging on artificial aging.However,the related mechanism is not clear yet and needs to be studied in depth.Therefore,the commercial 6063 aluminum alloy((Mg+Si)%?1wt.%)after different NA treatments was selected in this paper to study the effect of AA temperature on the mechanical properties of the alloy and precipitation behavior of the alloy.Through hardness analysis and transmission electron microscopy(TEM),the mechanical properties and microstructure of the samples were characterized to explore the AA temperature regulation mechanism of alloy peak hardness.In-situ resistance technology is used to monitor the resistance change during the aging process of the sample and describe the evolution of the microstructure during the aging process of the alloy.Atom probe tomography(APT)was used to accurately characterize the clusters of short-term artificial aging samples,and an in-depth analysis of the precipitation behavior of alloys under different temperature conditions was carried out.The results show that the NA before AA affects the AA precipitation process adversely under lower AA temperatures,e.g.150?,by suppressing the peak aging hardness,while such effect can be modulated to be positive by increasing AA temperature to over 175?.Under higher AA temperatures,transformation of clusters into main strengthening precipitates,?" phase for example,is promoted.The nucleation probability of these phases is enhanced,through lowering the nucleation energy barrier.As a result,the NA clusters facilitate nucleation and growth of the main precipitates during AA.This research work is helpful for the automobile production industry to understand the commercial 6063 aluminum alloy room temperature parking effect and artificial aging process.The relevant data and theoretical basis in this study have important guiding significance for the production of 6063 aluminum alloy and artificial aging process.