倒锥形通道浇注制备半固态7075铝合金浆料

采用倒锥形通道浇注方法制备了半固态7075铝合金浆料.试验结果表明,当浇注温度为660～690℃、通道内壁锥度在2°～6°之间时,采用锥形通道浇注方法可以制备出较高品质的半固态7075铝合金浆料,且通道内挂料较少；当通道内壁锥度一定时,随着浇注温度降低,初生α -Al的平均晶粒尺寸减小、形状因子提高；当浇注温度一定时,随着通道内壁锥度的增大,初生α -Al的平均晶粒尺寸减小、形状因子提高；在倒锥形通道浇注制备半固态7075铝合金浆料过程中,通道内壁的大量形核和晶粒游离及收集坩埚中的晶粒熟化是获得细小球状初生α-Al晶粒的主要原因.

Preparation of Semi-Solid 7075 Aluminum Alloy Slurry Poured through an Inverted Cone Channel

The semi-solid slurry of 7075 aluminum alloy was prepared with an inverted cone channel.The experimental results indicate that the semi-solid 7075 aluminum alloy slurry with satisfied quality can be produced with the inverted cone pouring pipe,and there exhibits only a thin layer on solidified shell inside the pipe with the pouring temperature of 660 ℃～690 ℃ and the inner wall conicity of 2°～6°.With a fixed conicity,the equivalent size of the primary α-Al grains is decreased and the shape factor is increased with decreasing in pouring temperature.With a given pouring temperature,the equivalent size of the primary α-Al grains is decreased and the shape factor is increased with the increase of conicity.The experimental results also show that a large number of nuclei of primary α-Al grains are formed on the inner surface of the inverted cone pipe,and most of them can be separated from the inner surface as well as grain ripen in the containing crucible during the slurry preparation,which is responsible for the generation of fine spherical primary α-Al grains.