| .In order to study the effect of Cu element and heat treatment on the structure and properties of 6016 aluminum alloy,the composition of 6016aluminum alloy was adjusted to increase the content of Cu element?0.1%by weight?,and the influence of Cu element on the microstructure,mechanical properties,baking properties and intergranular corrosion properties of aluminum alloy were studied.The effects of different quenching media on the mechanical properties and intergranular corrosion properties of 6016 aluminum alloy after natural aging were investigated,and the conclusions are as follows:?1?After increasing Cu content,the grains of 6016 aluminum alloy are refined.The microstructure of as-cast alloys with little or more copper is mainly composed of?phase?AlFeSi?,hypereutectic Si and Mg2Si phase,and Q?AlCuMgSi?phase appears in the alloy containing more copper.?2?With the increase of aging time,the electrical conductivity of the alloy increases continuously;The higher the aging temperature of the alloy is,the higher the conductivity is,and the conductivity of the alloy with higher Cu content is lower;the mechanical properties of the alloy with more Cu are improved both in T4p state and after baking,and the time for the alloy to reach of the peak of strength is shorter,when aging at 160?,180?and 200?,the time is shortened by 12.5%,25%and 11%respectively;With the increase of aging time,the intergranular corrosion resistance of the two alloys decreases gradually.In the later stage of aging,the corrosion type gradually changes from intergranular corrosion to pitting corrosion,and the intergranular corrosion resistance is increased by 75.2%141%.?3?With the extension of natural aging time,the hardness,yield strength and tensile strength of the alloys increase,and the conductivity and elongation decrease.The larger the quenching cooling rate is,the greater the hardness value is,and the smaller the conductivity value is.However,the total elongation has little change,and the elongation of the alloy quenched with 0?water is the smallest.After artificial aging,the intergranular corrosion resistance of the alloy quenched in the medium with higher cooling rate is better,and its resistance to intergranular corrosion has been greatly improved.?4?After 21 days of natural aging,there are two kinds of precipitates near the grain boundary of the alloy:?1?spherical or ellipsoidal black precipitates,which are distributed near the grain boundary or in the grains,and also a small part on the grain boundary;?2?elongated black precipitates,which mainly appears in the samples quenched in air or 90?water. |
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