【摘要】 研究了短时电磁搅拌、细化剂及二者复合作用对7A04铝合金大体积半固态浆料组织及其径向均匀性的影响。结果表明:短时电磁搅拌和添加晶粒细化元素Zr,Sc均可使7A04铝合金半固态浆料组织的初生α-Al晶粒细化和圆整,并提高组织均匀性;短时电磁搅拌和细化剂复合作用的7A04铝合金半固态浆料具有最佳的组织,在631℃下,其晶粒直径和圆整度分别为36μm和0.68,在直径180 mm的制浆室中浆料组织尺寸的变异系数C_V仅为0.8%;随着温度降低,7A04铝合金半固态浆料组织的尺寸变大,均匀性变差,但圆整度的变化不大。更多还原

【Abstract】 The effects of short-time electromagnetic stirring(EMS), grain refiners and their combined effects on microstructure and radial homogeneity of large-volume semisolid slurry of 7A04 alloy were investigated. The results indicate that 7A04 alloy semisolid slurry with fine and globular primary α-Al grains can be achieved and the homogeneity of slurry is improved by either short-time EMS or addition of grain refining elements Zr and Sc. Optimum microstructure with average equivalent diameter of 36 mm, shape factor of 0.68, coefficient of variation C_v of 0.8% at 631 °C is obtained by the combined action of short-time EMS and grain refiners. As the temperature decreases, the microstructure of semisolid slurry of 7A04 alloy coarsens and the microstructure homogeneity of the slurry deteriorates, while the shape factor has little change.更多还原