摘要
利用多尺度模拟方法研究了半连续铸造时浇注温度对合金凝固组织的影响。建立了描述连续铸造过程的温度场模型及相变模型,通过固相率变化将宏观尺度上的温度场计算和介观尺度上的微观组织模拟耦合起来,将计算得到的Al-Cu合金在宏观尺度上的稳态温度场数据映射到介观尺度上,利用液固相变区域中元胞的平均过冷度确定连续铸造过程中各个元胞的形核。用元胞自动机方法计算Al-Cu合金在Cu含量为8%和10%(质量分数,下同)、铸造速度为2.0mm/s、浇注温度分别高于液相线50K和5K以及液相线时的凝固组织。计算表明,近液相线浇注可获得比常规铸造更好的凝固组织,Cu含量为8%和10%的Al-Cu合金,可在较大的近液相线温度范围内获得晶粒大小和分布良好的合金组织。
The influence of pouring temperature on the solidified microstructure of Al-Cu alloy in semi-continuous casting has been simulated by a multi-scale simulation method.The modelings of temperature field and phase transformation in Al-Cu alloy in semi-continuous casting have been established based on coupling temperature field with microstructure evolution through solid fraction change.The calculated steady temperature field in the Al-Cu alloy was projected to a mesoscale area to determine the nucleation of cell in semi-continuous casting by calculating the average under-cooled rate of cell in liquid-solid phase transformation zone.The microstructures of the Al-Cu alloy with contents of 8% and 10% Cu have been simulated by the cellular atomaton poured at different temperature,including 50 K and 5 K higher than liquidus temperature as well as liquidus temperature with the casting velocity of 2 mm/s.The results indicate that the microstructure of Al-Cu alloy poured at near-liquidus temperature is superior to that of ones in conventional casting.The desirable microstructure with excellent grain size and distribution can be prepared with pouring at a larger range of near-liquidus temperature with the Cu content more than 8% or 10%.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2008年第4期247-250,共4页
Special Casting & Nonferrous Alloys
基金
国家自然科学基金资助项目(50674032)
教育部新世纪优秀人才支持计划项目(NCET-04-0279)
关键词
半固态
多尺度模拟
近液相线铸造
液固相变
Semi-solid,Multi-scale Simulation,Near-liquidus Pouring,Liquid-solid Phase Transformation
