单向凝固中温度梯度和凝固速度对铝硅合金共晶生长形态的影响  

Effect of Temperature Gradient and Solidification Rate on Eutectic Growth of Al-Si Alloy During Unidirectional Solidification

作　　者：黄婉如[1] 廖恒成[1] 吴申庆[1] 孙国雄[1] 

机构地区：[1]东南大学材料科学与工程学院,江苏南京211189

出　　处：《铸造》2010年第3期239-242,246,共5页Foundry

基　　金：国家自然科学基金资助项目(50771031)

摘　　要：对Al-13Si-0.2Sr-0.35Mg合金进行了一系列单向凝固实验,研究了界面前沿温度梯度GL和生长速度R对铝硅合金共晶生长形态的影响。结果表明,GL和R对Sr变质的非小面-小面Al-Si体系共晶生长的影响符合界面稳定性理论,随着R的增大和GL的减小,界面前沿成分过冷变大,共晶体生长形貌经历了从平界面失稳到胞状晶、胞状树枝晶、柱状树枝晶和等轴晶转变。Al-13Si-0.2Sr-0.35Mg alloys were solidified directionally to investigate effect of temperature gradient GL and growth velocity R on eutectic growth and grain morphology of Al-Si alloy. Results show that effect of GL and R on stability of eutectic growth in nonfaceted-faceted AI-Si system modified with strontium is in accord with the interface stability theory for eutectic growth. With increase in R or decrease in GL, constitutional supercooling is increasingly produced in front of liquid/solid interface of eutectic, and hence, eutectic growth changes from planar front into cellular, cellular-dendrite, columnar dendrite and even into equiaxed grains.

关 键 词：铝硅合金 单向凝固 共晶生长 凝固速度 温度梯度 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG21[金属学及工艺—金属材料]