旋转摩擦挤压7075铝合金组织及第二相形貌

发布时间：2018-09-01 07:13

【摘要】：采用旋转摩擦挤压法(RFE)加工T6态7075铝合金,对挤压后的7075铝合金进行热处理,观察了7075铝合金的显微组织和第二相变化,测试了加工后材料的显微硬度。结果表明,RFE态的7075铝合金为未完全再结晶的细小等轴晶,平均晶粒尺寸约为15μm。经热处理后,铝合金中未发生再结晶的晶粒继续完成再结晶,晶粒尺寸进一步细化均匀,约为8μm。RFE加工使7075铝合金中保留的初生金属间化合物尺寸变小,原沉淀析出的第二相(MgZn_2相)在RFE加工过程中大部分发生重溶,未重溶的MgZn_2相发生粗化,经热处理后7075铝合金中析出的MgZn_2相尺寸细小,呈弥散分布。RFE态7075铝合金显微硬度低于基材,但经T6热处理后,其硬度为177.5HV,高于基材,7075铝合金中第二相对基体的强化效果较细晶强化作用更显著。
[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.
【作者单位】：南昌航空大学轻合金加工科学与技术国防重点学科实验室;
【基金】：国家自然科学基金资助项目(51364037)~~
【分类号】：TG146.21;TG379

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