抽拉速率和过热温度对Zn-5%Al合金定向凝固界面的影响  

Effect of Withdrawal Rate and Superheat Temperature on Interface of Unidirectionally Solidificated Zn-5%Al Alloy

作　　者：杨付双[1] 倪锋[2] 

机构地区：[1]铜陵学院机械工程系,安徽铜陵244000 [2]河南科技大学材料科学与工程学院,河南洛阳471003

出　　处：《铸造技术》2010年第4期440-444,共5页Foundry Technology

基　　金：安徽省高校青年教师科研资助计划项目(编号:2006jq1240)

摘　　要：采用Zn-5%Al合金,对不同抽拉速率和过热条件下的定向凝固界面进行研究。结果表明,当合金熔体的过热温度为450℃时,随着抽拉速率从1.1μm/s增加到11.1μm/s,液固界面呈现平面—细胞—胞枝变化,与一般的界面形态演化相符;当熔体的过热温度为610℃时,在相同的抽拉速率条件下,液固界面呈现平胞—平面—枝晶变化,不同于一般的界面形态演化。采用界面稳定性动力学理论分析了抽拉速率和过热温度对液固界面的影响,得出定向凝固界面稳定性变化,存在着若干个由抽拉速率和过热互相制约决定的分界点。Unidirectional solidification experiments were carried out on Zn-5% AI alloy with different withdrawal rates and superheat temperatures. It was showed that the morphology of liquid/solid interface varied with withdrawal rate and superheat temperature. When superheat temperature of alloy melt was 450 ℃ and as withdrawal rate increased from 1. 1 μm/s to 11. 1μm/s, the morphology of liquid/solid interface varied from plane, cells to dendrites, it showed the changes just as the same as common interface. While as superheat temperature of the melt was 610 ℃ with the same withdrawal rate increment, the morphology of interface varied from cells, plane to dendrites, that varies in different way from common interface. Effects of withdrawal rate and superheat temperature on interface was studied by Mullins and Sekerka＇s steady-state solution, as a result, the interface steady-state in unidirectional solidification is partitioned by some boundary which is determined by withdrawal rate and superheat.

关 键 词：Zn-5%Al合金 抽拉速率 过热温度 定向凝固 液固界面 

分 类 号：TG111.4[金属学及工艺—物理冶金]