半固态A356铝合金浆料的LSPWES制备和流变成形  

Slurry Preparation by LSPWES Method and Rheocasting of A356 Aluminum Alloy

作　　者：毛卫民[1] 朱达平[1] 郑秋[1] 汤国兴[1] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083

出　　处：《铸造》2009年第1期10-13,共4页Foundry

基　　金：国家863计划项目(2006AA03Z115);国家重点基础研究发展规划项目(2006CB605203);国家自然科学基金项目(50374012)

摘　　要：利用短时弱电磁搅拌和低过热度浇注（LSPWES）制备了半固态AISi7Mg铝合金浆料，随后对该浆料进行了均热处理，并探讨了压射比压对铝合金浆料流变挤压铸造过程的影响。制备结果表明：在630-650℃下浇注，同时附以短时低强度电磁搅拌，AISi7Mg合金中的初生α-Al呈现为球状，个别的初生α-Al呈现为蔷薇状；在固液两相区进行均热处理时，促进了初生α-Al的熟化作用，使初生α-Al进一步球化和粗化。压射比压对半固态AISi7Mg合金浆料的充填性影响较大，压射比压越高，型腔越容易充满；对于本试验条件，只要压射比压≥34MPa，半固态AlSi7Mg合金浆料都可充满型腔。流变挤压铸件的组织分布很均匀，表明采用低过热度浇注和弱电磁搅拌相结合所制备的半固态AlSi7Mg铝合金浆料适合流变挤压成形，有利于获得高质量的压铸件。The semisolid slurry of AlSi7Mg alloy was prepared by low superheat pouring and slight electromagnetic stirring field at a low power for a short time, and then the slurry was further soaked for proper time and finally rheo-squeeze-cast into a machine part. The influence of the specific pressure on the rheo-squeeze-cast process was also studied. The experimental results show that if the melt of AlSi7Mg alloy is poured at 630-650 ℃ and meanwhile stirred by slight electromagnetic field for a short time, the most primary α-Al grains solidified in the slurry are spherical and only a few are rosette-like. If the slurry is then homogeneously soaked in the liquidus-solidus range for some time, the ripening of primary α-Al is developed further and it becomes more spherical and larger. The experimental results also show that the injection pressure has great influence on the filling ability. The higher the injection pressure, the higher the slurry filling ability, in this test, if only the injection pressure is equal to or more than 34 MPa, the given casting＇s cavity can be filled completely. The microstructural distribution in the casting is very homogeneous and it shows that the slurry prepared by above-mentioned method is very suitable for rheoforming and helpful for obtaining high quality castings.

关 键 词：半固态 电磁搅拌 流变挤压 显微组织 ALSI7MG合金 

分 类 号：TG249.9[金属学及工艺—铸造]