摘要
在悬浮铸造的基础上引入了电磁搅拌,并将其与悬浮铸造的优点有机结合,通过不同电磁搅拌时间对悬浮铸造AZ61变形镁合金进行了试验,悬浮剂的加入使合金液中形成了大的能量起伏和成分起伏,有助于形成细晶组织,电磁搅拌的引入加速了悬浮剂和合金母液的均匀混合,有效避免了悬浮剂在合金液中的聚集"搭桥"现象和悬浮剂在铸件中的夹生,结果表明在悬浮剂为2%(质量分数)时进行2 min搅拌时效果最佳,组织的平均晶粒度最小,达到57.5μm,是悬浮铸造时的三分之一,是金属型铸造的四分之一.析出相Mg_(17)Al_(12)明显减少和细化,并且在基体上的分布更加弥散.电磁悬浮铸造(2 min,2%)对比金属型铸造,抗拉强度提高了约20%,屈服强度提高了约30%,延伸率提高了近50%.
Electromagnetic suspension casting is proposed, which combines the virtues of the electromagnetic stirring and the suspension casting. The suspension parcels increase the thermal and constitutional undercooling at the advance S/L interface. The electromagnetic stirring improves the distribution uniformity of the suspension particles in melting alloy. The suspension casting of wrought AZ61 magnesium alloy with different electromagnetic stirring time was investigated. The results show that the finest grain size is obtained when the electromagnetic stirring time was 2 min and the amount of the suspension particles was 2%（mass fraction）. The average grain size is 57.5 μm, which is one third of the grain size in the suspension casting, and one quarter in the die casting. Moreover, thin β-Mg17Al12 phase is observed, the distribution uniformity of β-Mg17Al12 phase is improved, and the yield strength, the ultimate tensile strength and elongation of specimens obtained by the electromagnetic suspension casting has increased 20%, 30% and 50% respectively compared to the die-casting.
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2007年第5期491-495,共5页
Chinese Journal of Materials Research
基金
国家自然科学基金50475157
重点基金50234022及教育部重点项目105052资助.
关键词
金属材料
电磁-悬浮
晶粒细化
晶粒度
metallic materials, electromagnetic suspension, grain refinement, grain degree
