双螺旋流变压铸AZ91D镁合金的研究  

Rheo-Die Casting of AZ91D Magnesium Alloy by Twin-Screw Stirring

作　　者：马跃宇[1] 杨必成[2] 王亚宝[2] 徐骏[2] 

机构地区：[1]北京有色金属研究总院科技信息研究所,北京100088 [2]北京有色金属研究总院国家有色金属复合材料工程技术研究中心,北京100088

出　　处：《稀有金属》2013年第1期27-32,共6页Chinese Journal of Rare Metals

基　　金：国家科技部国际合作项目(2009DFB50210)

摘　　要：液态压铸是镁合金最主要的成形方式,但液态压铸件存在气孔等缺陷,限制了镁合金的进一步推广使用。介绍了采用双螺旋流变制浆技术,对镁合金AZ91D进行了流变压铸研究。首先,将镁合金AZ91D熔体浇入到双螺旋流变制浆机中,然后根据不同工艺参数制备流变镁合金浆料,待制浆结束后,将半固态浆料转移到压铸机内,制得半固态压铸件。采用Micro-Image Analysis&Process(MIAP)软件分析了双螺旋流变制浆工艺参数(搅拌温度、搅拌时间和转速)对镁合金AZ91D的初生相晶粒大小的影响,并研究了镁合金压铸成形性。结果表明:随着搅拌温度的降低,晶粒尺寸变化不是很大;随着搅拌时间延长,镁合金晶粒尺寸逐渐增大;随着搅拌速度的增加,镁合金平均晶粒尺寸减少。镁合金流变压铸件中的初生α相由搅拌中形成的球状晶及压铸过程中二次凝固形成的更为细小的球状晶组成。对比了普通压铸件与流变压铸件热处理后的力学性能,流变压铸件的力学性能得到大幅提高,其原因归结为铸态组织的细小和均匀化。The liquid die casting is the main forming technique of magnesium alloys. However, in die cast components, some defects such as pores and so on restrained further applications of magnesium alloys. In this paper, rheo-die casting of AZ91D magnesium alloy prepared by twin-screw stirring technique was studied. Firstly, AZ91D magnesium alloy melt was put into a twin-screw stirring ma- chine; then, rheo-slurries were fabricated by twin-screw stirring according to different parameters. Lastly, the slurries were transferred into a die casting machine and rheo-die casting components were made. Effects of rheo-slurries processing parameters （temperature, time and speed） on the sizes of primary phase and performances of the die cast components were researched. The results showed that the grains changed little with the temperatures decreasing. When the stirring time increased, the grains became larger. With the stirring speed faster and faster, the grains became smaller and smaller. The primary phase of the rheo-die cast components was composed of globular crystals formed in the stirring process and fine globular crystals produced in the secondary solidifieation during the rheo-die casting. Compared mechanical properties of the liquid die cast components with those of the rheo-die cast components, mechanical performances of the rheo- die cast eomponents were improved largely due to their fine and even sizes.

关 键 词：流变压铸 液态压铸 镁合金 双螺旋搅拌 

分 类 号：TG146.22[一般工业技术—材料科学与工程]