半连铸工艺对AZ31镁合金铸锭组织的影响  

Effect of semi-continuous casting processing on ingot microstructure of AZ31 magnesium alloy

作　　者：赵辉[1] 彭晓东[1,2] 王艳光[1] 赵凯阳[1] 魏群义[1,2] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400045 [2]国家镁合金材料工程技术研究中心,重庆400044

出　　处：《兵器材料科学与工程》2011年第6期22-26,共5页Ordnance Material Science and Engineering

基　　金：国家"973"重大基础科研项目(2007CB613702);科技部国际合作项目(2010DFR50010)

摘　　要：用传统的半连续铸造工艺制备90 mm AZ31镁合金圆柱铸锭,利用光学显微镜(OM)和扫描电镜(SEM)观察并分析不同二次冷却水量和抽坯速度对显微组织的影响规律。结果表明:铸锭内存在大量一次及较发达的二次枝晶;随着冷却水量的增加,冷却速度增大,铸锭组织逐渐变得细小均匀;当冷却水量为58 L/min时达到极值,此后组织不再明显变化。拉坯速度的变化对组织影响不大。且受二次冷却水单向导热的影响,试样的纵截面存在粗大的蔷薇状枝晶和尺寸较长的柱状晶。由于结晶器的相对高度较大,铸锭由内到外的组织有增大趋势。The round -90 mm AZ31 magnesium alloy ingots were prepared by traditional semi-continuous casting process,the influence of cooling water and casting speed on microstructures of as-cast alloys was analysed by Optical Microscope（OM） and Scanning Electrical Microscope（SEM）.The results indicate that there exists massive primary dendrite crystals and the developed secondary dendrite crystals in the as-cast ingot;when the flux of cooling water is 58 L/min,fine and uniform microstructure can be obtained,and the microstructure does not change obviously with the cooling rate;the casting speed has little effect on the as-cast microstructures.With the influence of the unidirectional heat conduction of secondary cooling water,the thick rosette crystal and long columnar crystal exist in the vertical section of specimen.Because of the big relative height of the crystallizer used in this experiment,the crystals have an increase trend from inside to outside of ingot.

关 键 词：镁合金 半连铸 铸造工艺 微观组织 

分 类 号：TG244[金属学及工艺—铸造]