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依据强制对流搅拌原理,成功自主研制出强制对流搅拌(FCM)制浆设备,并与压铸机相结合,以AZ91D镁合金力学拉伸件为例,实现了浆料制备、输送到成形的一体化流变压铸过程;研究了不同FCM工艺参数下流变压铸件组织特征的演变;对比了不同工艺下压铸件力学性能的差异;并分析了FCM流变压铸工艺组织形成机理及凝固行为.结果表明:FCM工艺参数对铸件的显微组织有较大影响,适当提高螺杆转速或降低筒体温度,均有利于成形件组织形貌的改善;FCM流变压铸工艺不仅可以获得内部组织细小、圆整且分布均匀的成形件,而且可以显著提高成形件的力学性能;与传统压铸件相比,FCM流变压铸件的屈服强度变化不大,抗拉强度和延伸率分别提高了12.5%和80.0%;与经T4和T6热处理的铸件相比,铸态拉伸件的抗拉强度最低,屈服强度和伸长率介于T4和T6之间.
According to the principle of forced convection mixing, the forced convection mixing (FCM) pulping equipment was independently developed and combined with the die-casting machine to take AZ91D magnesium alloy mechanical tensile member as an example to realize the integration of slurry preparation and conveying to forming Rheological die-casting process, the evolution of the rheological die-casting structural characteristics under different FCM parameters was studied, the mechanical properties of the die-castings under different processes were compared, and the formation mechanism and the solidification behavior of the rheo-diecasting process were analyzed.The results show that: FCM process parameters have a significant impact on the microstructure of the castings. Appropriately increasing the screw speed or reducing the temperature of the cylinder are beneficial to the improvement of the microstructure of the formed parts. The FCM rheological die-casting process can not only obtain the fine and round internal structure Compared with the traditional die-castings, the yield strength of the FCM did not change much, and the tensile strength and elongation increased by 12.5% and 80.0% respectively. Compared with the castings treated with T4 and T6 heat treatment, the as-cast parts have the lowest tensile strength and the yield strength and elongation ranged from T4 to T6.