| 引用本文: | 王娜,周志敏,路贵民.近液相线铸造过程中近球形α相的形成机理[J].材料科学与工艺,2011,19(2):139-143.DOI:10.11951/j.issn.1005-0299.20110229. |
| WANG Na,ZHOU Zhi-min,LU Gui-min.Formation mechanism of sphere-like αphase in near-liquidus casting[J].Materials Science and Technology,2011,19(2):139-143.DOI:10.11951/j.issn.1005-0299.20110229. |
|
| 摘要: |
| 为从理论上弄清近液相线半连续铸造过程中铝合金半固态组织形成的基本规律和机制,研究了浇注温度、铸造速度和冷却强度等工艺参数对6061合金初生α相演变的影响,根据金相检测和多尺度计算机模拟结果,分析了近球形α相的形成机理.实验发现,在浇注温度为657℃、铸造速度为150 mm/min、冷却水流量为0.05 m3/min时可获得具有细小、分布均匀的近球形初生α相的6061半固态合金.理论分析和计算机模拟表明:晶粒周围浓度场的叠加将提高固/液界面的稳定性和晶粒在各个方向上生长的均匀性,促进近球形初生α相的形成;铸造工艺参数通过影响熔体内的形核率和长大速率决定最终的微观组织形貌特征;控制近液相线半连续铸造工艺参数可使熔体中的形核和长大过程达到合理匹配,从而获得优质的半固态浆料. |
| 关键词: 半固态成形 近液相线半连续铸造 初生α相 多尺度模拟 |
| DOI：10.11951/j.issn.1005-0299.20110229 |
| 分类号:TG249.9 |
| 基金项目:国家自然科学基金资助项目(50674032,51034002) |
|
| Formation mechanism of sphere-like αphase in near-liquidus casting |
|
WANG Na1, ZHOU Zhi-min1, LU Gui-min2
|
|
1.School of Sciences,Northeastern University,Shenyang 110004,China;2.School of Resources and Environmental Engineering,East China University of Science and Technology,Shanghai 200237,China
|
| Abstract: |
| This paper studied the influence of pouring temperature,casting velocity and cooling intensity on the microstructural evolution of 6061 alloy during near-liquidus semicontinuous casting(LSC) to clarify the formation mechanism of the semisolid microstructure.It was analyzed the formation of spherical primary α phase in melt according to the results of the metallographical measurement and the multi-scale computer simulation.It is experimentally found that the 6061 semisolid alloy with fine spherical primary α phase can be obtained by LSC under the conditions of the pouring temperature 657 ℃ the casting velocity 150 mm/min and the cooling water flux 0.05 m3/min.It is shown from the theoretical analysis and the multi-scale computer simulation that the overlapping solute fields of the adjacent growing grains will improve the stability of the moving solid-liquid interface and the uniformity of the grain growth in all directions,which facilitates the formation of globular primary α phase.The morphology of the primary α phase is determined by the rate of nucleation and that of grain growth in the melt,which can by achieved by adjusting the casting parameters.LSC can provide ideal technical parameters for an appropriate combination of the nucleation and the grain growth to result in the fine semisolid microstructure. |
| Key words: semisolid metal processing near-liquidus semicontinuous casting primary α phase multi-scale simulation |
