液相线半连续铸造112Al合金的组织

As-cast Microstructures of 112 Aluminium Alloy Cast by Liquids Semi-continuous Casting

液相线半连续铸造是 1种先进的半固态浆制备方法。考察了铸造温度、冷却强度及铸造速度对液相线半连续铸造法制备 112铝合金半固态浆料组织的影响。合金熔体在常规铸造温度 (690℃ )下浇注获得的锭坯边部是粗大的枝晶 ,中间部位组织极不均匀 ;在接近液相线温度以上 (60 5℃ )保温 2 0min后浇注的铸造组织较好 ,中心部位和边部组织的差异较小。在液相线温度 (5 88℃ )保温 2 0min后进行半连续铸造获得的锭坯中心和边部组织元均是均匀、细小的近球形组织。降低一次冷却强度、增大二次冷却强度和减小铸造速度均有利于均匀、细小、等轴的半固态组织的形成。结果表明 ,液相线半连续铸造能有效地制备

Liquidus semi continuous casting (LSC) is an advanced technology of semi solid slurries making. The as cast microstructures of 112 alloy cast by LSC at different casting temperature, cooling and casting velocity were studied . When the billet was cast from the conventional temperature (690 ℃), the border microstructures were coarse and dendritic, and the center microstructures were asymmetric. When the billet was cast from melt at (605 ℃) which was held for 20 min before casting, microstructures were uniform along the corss section. When the billet was cast from melt at 588 ℃ which was held for 20 min before casting, the microstructures were even uniform with fine and globular grains. Decreasing the first cooling rate and the casting velocity, increasing the second cooling rate were propitious to the fine, uniform globular grains. All those show that LSC is an efficient way for making 112 alloy's semi solid slurries.