弱搅拌功率对半固态AlSi7Mg合金浆料组织的影响

Effect of Weak Stirring Power on Microstructure of Semi-solid AlSi7Mg Alloy Slurry

本试验研究采用低过热度浇注和弱电磁搅拌制备浆料技术制备半固态AlSi7Mg合金浆料,研究了弱搅拌功率对合金浆料初生相α-Al形貌的影响以及浆料组织的径向分布。研究结果表明,在低过热度浇注和弱电磁搅拌条件下,当Al-Si7Mg合金液在浇注温度为630℃、搅拌功率为0.36kW时可制备出初生相α-Al形貌呈小而圆整的球状晶粒、组织分布均匀、直径为127mm的AlSi7Mg合金浆料;在低过热度浇注和弱电磁搅拌条件下,适当提高提高搅拌功率可改善初生相α-Al形貌,但当搅拌功率提高到一定程度,再增大搅拌功率,初生相α-Al形貌并没有得到明显改善;从半固态AlSi7Mg合金浆料组织的径向分布看,由边部到心部,浆料的组织形貌经历了一个枝晶组织向蔷薇状组织再向球状组织的转变过程。

The slurries of semi-solid AlSi7Mg alloy were made by low superheat pouring and weak electromagnetic stirring in this paper.The effects of stirring power on the slurry of semi-solid and microstructure morphology of AlSi7Mg alloy slurry in radial distribution were studied.The results showed that :at the condition of low superheat pouring and weak electromagnetic stirring ,when the pouring temperature is 630 ℃ and the stirring power is 0.36 kW,the slurry with 127mm in diameter,containing smaller spherical primary phase α-Al grains distributed homegeneously can be obtained .at the condition of low superheat pouring and weak electromagnetic stirring,raising the electromagnetic stirring reasonably could gain the better particle appearance of primary α-Al ,but the appearance of primary α-Al could not be improved well obviously when the electromagnetic stirring raised to a certain value.According to microstructures of semisolid AlSi7Mg alloy slurries in the radiation,microstructure morphology of slurries experienced a transition from dendritic morphology to rosette-like and globular or particle-like from the core to the edge of slurry.