【摘要】 提出了在电磁搅拌制备半固态A356铝合金浆料时插拔Cu棒的一个新工艺.由于在半固态铸锭轴向区域引入低温,可进一步提高电磁搅拌效果,铸锭各部位均由细小α-Al晶粒组成.该工艺还可适当提高低过热度浇注的温度而有利于实际生产.更多还原

【Abstract】 Because of the solidifying characteristic of alloy and the difference in thermal conductivity of mould,the microstructures of different zones of semi-solid slurry are different,which is hard to satisfy the requirement of rheoforming.A new process preparing semi-solid slurry is proposed,in which a locally rapid cooling near the center zone of mould can be realized by inserting a copper rod into the slurry and then pulling out repeatedly,except application of a weakly electromagnetic stirring. Semi-solid A356 alloy slurry was prepared by the new process and the effects of the new process on morphology and size of primaryα-Al in semi-solid A356 were researched.The results indicate that the nucleation rate,morphology and grain size of primaryα-Al are markedly improved by the new process.Primaryα-Al with small size presents particle-like or globular-like and distributes uniformly in the slurry even at lower overheating.The grain refining and structural homogeneity are relative to homogenization of the temperature field in the mould.更多还原