摘要
该文借助金相、电镜和热分析等手段，研究微量混合稀土（０．０５％～０．５０％，质量分数）对Ａｌ－７Ｓｉ－４Ｃｕ合金铸态组织与硬度的影响。结果表明，凝固速度显著影响稀土对共晶硅相的变质效果，稀土减小α（Ａｌ）二次枝晶间距，并使合金铸态硬度提高。微量稀土富集于α（Ａｌ）－Ｓｉ相界α（Ａｌ）－Ａｌ２Ｃｕ相界甚微。试验证实，稀土使合金中花纹状三元共晶α（Ａｌ）＋Ｓｉ＋Ａｌ２Ｃｕ减少。
The influence of minor addition (0.05 %￣0.50 %, mass %) of mischmetal on cast structure and hardness of Al 7Si 4Cu alloy is studied by using metallographic analysis,electronmicroscope and thermal analysis. The results reveal that the solidification rate has a noticeable influence on the effect of modification of rare earth on eutectic Si phase. Rare earth can decrease the α(Al) secondary dendrite arm spacings and increase the cast hardness of this alloy. Minor additoin of rare earth is rich in α (Al) Si interface, but minimal in α (Al) Al 2Cu interface. Experiments show the possibility to make the proportion of fine ( α +Si+Al 2Cu) eutectic decrease and the proportion of block lke Al 2Cu phase increase.
出处
《南京理工大学学报》
EI
CAS
CSCD
1997年第2期157-160,88,共4页
Journal of Nanjing University of Science and Technology
基金
国防科技重点预研行业基金
关键词
铝合金
铸造合金
铸态组织
硬度
稀土元素
aluminium alloys, cast alloys, mischmetal, cast structure, hardness
Al Si Cu system
