铸造速度对Al-Cu合金半固态组织影响的多尺度模拟

用多尺度模拟方法研究了半连续铸造过程与Zl201合金成分近似的5%Al-Cu合金凝固组织受铸造速度的影响。建立了温度场模型和相变模型。通过固相率的变化把温度场计算和微观组织模拟从宏观尺度和介观尺度耦合起来。将宏观尺度上计算出的稳态温度场映射到介观尺度上。利用液固相变区中原胞的平均过冷度确定半连续铸造过程中各元胞的形核,采用溶质扩散模型描述晶粒长大。针对选定对象模拟了浇铸温度为930 K,铸造速度在(1.5～3.5)mm/s时微观组织的演变。结果表明,当铸造速度在2.0 mm/s时得到的微观组织均匀、细小,模拟结果与实验结果吻合。

Multi-Scale Simulation of Influence of Casting Speed on Microstrure Evolutin of Al-Cu Ally

The influence of casting speed on the solidified structure of 5%Al-Cu alloy same to ZL201 alloy during semi-continuous casting was investigated by a multi-scale simulation method.The models of temperature field and phase transformation were established for the casting and the change in solid fraction was available to couple the macro-scale simulation with meso-scale one .The change in steady temperature field was projected to a macro-scale area to determine the nucleation of cell in transformation zone. The grain growing process was described by solute diffusion model.The Microstructure evolution was simulated during near liquidus casting at casting speed of 1.5~3.5mm/s,respectively,with pouring temperature 930K.The results show that the simulation results are well consistent with the experimental results.