浇注扰动对近液相线铸造半固态AlSi9Mg合金的影响  

Effect of Pouring Disturbance on Preparation of Semi-Solid AlSi9Mg Alloy by Near Liquidus Casting

作　　者：弭光宝[1] 薛克敏[2] 韩国民[2] 李培杰[1] 

机构地区：[1]清华大学新材料国际研发中心,北京100084 [2]合肥工业大学材料科学与工程学院,安徽合肥230009

出　　处：《铸造》2009年第7期671-676,共6页Foundry

基　　金：安徽省自然科学基金(070414148);国家重点基础研究发展计划项目(2007CB613702)资助

摘　　要：通过设计正交试验,结合金相分析获得了试验条件下近液相线铸造法制备半固态AlSi9Mg合金的合理工艺参数匹配,即浇注温度605℃、浇注高度3 h型、保温时间35 min、冷却强度适中(水冷)时获得的非枝晶组织更加细小、圆整且分布均匀;从晶粒形核、长大的热力学和动力学角度,综合分析了浇注扰动对近球形或球形非枝晶组织形成的影响机制。结果表明,浇注扰动不仅可大大提高形核率,且利于晶粒直接球化长大和等轴枝晶形成后的球化生长;提高晶粒球形长大的稳定性并将长大后的球晶保留下来或增强枝晶形成后的球化生长趋向是获得理想非枝晶组织的关键。The ideal technological parameters matching for preparing the semi-solid slurries of AISi9Mg alloy under the experimental condition was gained by the designed orthogonal test as well as metallographic analysis. The results show that the optimal technological parameters are： pouring temperature 605 ℃, pouring height 3 hmouid, holding time 35 min and the proper cooling strength （water quenching） . Based on thermodynamics and dynamics of crystal grain nucleation and growth, the influence of pouring disturbance on the formation of near globular or globular crystals was synthetically analyzed. The results indicate that pouring disturbance can not only increase the nucleation rate greatly, but also promote the direct globular growth of the grain and enhance the globuling growth of the equiaxed dendrite structure. Increasing the stability of globuling growth for grains or enhancing tendency of globuling growth for dendrite crystals is the key to obtain ideal non-dendrite structure.

关 键 词：近液相线铸造 浇注扰动 AlSi9Mg合金 非枝晶组织形成机制 

分 类 号：TG249.9[金属学及工艺—铸造] TG146.2[一般工业技术—材料科学与工程]