半连续铸造组织的多尺度模拟及半固态合金设计  

Multi-scale Simulation of Microstructural Evolution in Semi-continuous Casting and Semi-solid Alloy Design

作　　者：周志敏[1] 邓叙燕[1] 王娜[1,2] 路贵民[3] 

机构地区：[1]东北大学材料物理与化学研究所 [2]东北大学材料电磁过程研究教育部重点实验室 [3]华东理工大学资源与环境工程学院

出　　处：《特种铸造及有色合金》2009年第1期19-23,共5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(NCET-04-0279)

摘　　要：用多尺度模拟方法研究了半连续铸造过程中微观组织的演变,提出了基于微观组织演变模拟的半固态合金设计方法。针对连续铸造过程建立了温度场及相变模型,通过固相率变化将宏观和介观尺度的计算联系起来;用外推法建立的连续铸造出口处的非物理边界条件对稳态温度场的计算精确高效;通过多尺度模拟研究了合金成分、浇注温度和浇注速度对Al-Cu合金凝固组织及成分分布的影响。结果表明:晶粒以枝晶方式生长,不同取向的相邻晶粒相遇时形成Cu合金含量较高的晶界;当Cu合金含量为8.00%时,铸造速度和浇注温度对组织形貌的影响较小,可获得大小和分布均匀的半固态合金组织。对ZL201合金的近液相线铸造组织的模拟结果与试验结果吻合。研究表明多尺度模拟是半固态合金设计及其工艺参数预测的有效方法。Microstructural evolution of Al-Cu alloy in semi-continuous casting was simulated by means of a multi-scale calculation method. A new method for semi-solid alloy design was proposed on the basis of microstructural simulation. Temperature field and phase transformation models were established to simutate continuous casting, in which solid fraction was used to couple the calculation of macro-scale and mesoscale. Non-physical boundary for outlet side of mold in continuous casting was established based on an extrapolation method, which exhibits high efficient accuracy for steady temperature field. Effects of chemical composition, pouring temperature and pouring velocity on microstructure and constituent distribution of Al-Cu alloy were simulated by the multi-scale model. The results reveal that grain is grown dendritically and form grain boundary with high alloy concentration due to the merging of adjacent grain with different orientations. The desirable semi-solid microstructure in the Al-Cu alloy can be observed with 8.0% Cu content, where microstructure of the alloy is slightly related to casting velocity and pouring temperature. The simulated results are well in agreement with experimental ones in ZL201 alloy, which shows that the multi-scale simulation is an effective method to simulate design of semi-solid alloy and to predict processing parameters.

关 键 词：多尺度模拟 半固态成形 近液相线铸造 液固相变 

分 类 号：TG249.7[金属学及工艺—铸造] TB115[理学—数学]