摘要
The influences of RE-modification and Sr-modification on the hydrogen content and surface oxide film of A356 aluminum alloy melt were investigated. The hydrogen content of the melt was measured by reduce pressure test. The phases in the surface oxide film were analyzed by X-ray diffractometry (XRD), and the morphology of the surface oxide film was observed by scanning electronic microscopy (SEM). The results show that RE-modification reduces the hydrogen content of A356 aluminum alloy greatly. Contrarily, Sr-modification increases the hydrogen content remarkably. After being treated with RE, a large number of LaAl11O18 consisting of Al2O3 and La2O3, are generated in the surface oxide film of A356 alloy. The surface oxide film of Sr-modification is almost composed of Al2SrO4. According to the results of SEM, the surface oxide film of Sr-modification is very easy to crack, destroy the continuity and compactness of surface oxide film, accelerate the vapor diffusing into the melt, consequently, increase the hydrogen content of A356 alloy melt significantly. But RE-modification makes the surface oxide film compact, and restrains the aluminum exposed to water, so reduces the hydrogen content of A356 alloy melt.
The influences of RE-modification and Sr-modification on the hydrogen content and surface oxide film ofA356 aluminum alloy melt were investigated. The hydrogen content of the melt was measured by reduce pressure test. The phases in the surface oxide film were analyzed by X-ray diffractometry （XRD）, and the morphology of the surface oxide film was observed by scanning electronic microscopy （SEM）. The results show that RE-modification reduces the hydrogen content ofA356 aluminum alloy greatly. Contrarily, Sr-modification increases the hydrogen content remarkably. After being treated with RE, a large number of LaAl11O18 consisting of Al2O3 and La2O3, are generated in the surface oxide film of A356 alloy. The surface oxide film of Sr-modification is almost composed of Al2SrO4. According to the results of SEM, the surface oxide film of Sr-modification is very easy to crack, destroy the continuity and compactness of surface oxide film, accelerate the vapor diffusing into the melt, consequently, increase the hydrogen content of A356 alloy melt significantly. But RE-modification makes the surface oxide film compact, and restrains the aluminum exposed to water, so reduces the hydrogen content ofA356 alloy melt.
出处
《中国有色金属学会会刊：英文版》
CSCD
2006年第A03期1425-1428,共4页
Transactions of Nonferrous Metals Society of China
关键词
铝合金
有限元分析
稀土元素
表面氧薄膜
A356 aluminum alloy
rare earth elements
surface oxide film
gas porosity
strontium
