【摘要】：采用旋轉(zhuǎn)摩擦擠壓法(RFE)加工T6態(tài)7075鋁合金,對擠壓后的7075鋁合金進行熱處理,觀察了7075鋁合金的顯微組織和第二相變化,測試了加工后材料的顯微硬度。結(jié)果表明,RFE態(tài)的7075鋁合金為未完全再結(jié)晶的細小等軸晶,平均晶粒尺寸約為15μm。經(jīng)熱處理后,鋁合金中未發(fā)生再結(jié)晶的晶粒繼續(xù)完成再結(jié)晶,晶粒尺寸進一步細化均勻,約為8μm。RFE加工使7075鋁合金中保留的初生金屬間化合物尺寸變小,原沉淀析出的第二相(MgZn_2相)在RFE加工過程中大部分發(fā)生重溶,未重溶的MgZn_2相發(fā)生粗化,經(jīng)熱處理后7075鋁合金中析出的MgZn_2相尺寸細小,呈彌散分布。RFE態(tài)7075鋁合金顯微硬度低于基材,但經(jīng)T6熱處理后,其硬度為177.5HV,高于基材,7075鋁合金中第二相對基體的強化效果較細晶強化作用更顯著。
[Abstract]:T6 7075 aluminum alloy was machined by rotating friction extrusion (RFE). 7075 aluminum alloy after extrusion was treated by heat treatment. The microstructure and the second phase of 7075 aluminum alloy were observed. The microhardness of the processed material was tested. The results show that the 7075 aluminum alloy is not fully recrystallized with fine equiaxed crystal, and the average grain size is about 15 渭 m. After heat treatment, the grains without recrystallization in aluminum alloy continued to be recrystallized, and the grain size was further refined and uniform. The size of primary intermetallic compounds retained in 7075 aluminum alloy was reduced by processing about 8 渭 m.RFE. The second phase (MgZn_2 phase) precipitated from the original precipitation occurs redissolution in the process of RFE processing and coarsening of the unredissolved MgZn_2 phase. The size of the MgZn_2 phase precipitated in 7075 aluminum alloy after heat treatment is small. The microhardness of 7075 aluminum alloy with dispersion distribution is lower than that of substrate, but after T6 heat treatment, the hardness of 7075 aluminum alloy is 177.5HV. the strengthening effect of 7075 aluminum alloy is more obvious than that of fine grain strengthening.
【作者單位】： 南昌航空大學(xué)輕合金加工科學(xué)與技術(shù)國防重點學(xué)科實驗室;
【基金】：國家自然科學(xué)基金資助項目(51364037)~~
【分類號】：TG146.21;TG379

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