The Study of Trace Be on Al-11%Si and 319 Aluminum Casting Alloys Containing 1pct Iron Impurity

• Main Authors: Shan-Noon Yie, 易善穠
• Other Authors: Sheng-Long Lee
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/94839304138228235070

博士 === 國立中央大學 === 機械工程研究所 === 88 === The studies of present works are (I) the effect of various contents of Be on Al-11%Si aluminum casting alloy and (II) the effect of 0.1% Be on 319 aluminum casting alloy with various solution treatment temperatures. Both contain 1pct iron impurity. It may summarize the conclusion as: (I) The effect of various contents of Be on Al-11%Si aluminum casting alloy: Increasing the content of Be shortens the lengths of iron-rich phase and flake silicon. The content of Be more than 0.2% makes the morphology of Chinese script iron-rich phase transformed complete. Increasing the content of Be icreases the ductility of Al-11%Si aluminum casting alloy containing 1pct iron impurity. Increasing the content of Sr do not affect the transformation of Chinese script iron-rich phase from needle iron-rich phase in Al-11%Si aluminum casting alloy. (II) The effect of 0.1% Be on 319 aluminum casting alloy with various solution treatment temperatures: Be element dispersed in aluminum matrix will cluster silicon particle and iron-rich phase. But the clustering ability of thermal is superior to Be. The same as that in Al-11%Si aluminum casting alloy, Be transforms needle iron-rich phase into Chinese script iron-rich phase, not affected by the presence of elements of Cu, Mg, etc. Increasing the solution temperature, the precipitation temperature will be promoted and the precipitation quantity will be increased by the pre-existing Be as inoculat in the matrixe. Be stablizes the dual Al-CuAl2 eutectic phase, promoting the eutectic temperature about 7-9℃. Needle iron-rich phase broken by thermal is at about 510℃ and the connection of Chinese script iron-rich phases is at about 530℃. To avoid the dumb of ductility by the ultra-fine structure, it is suggested that solution temperature of 319 aluminum casting alloy is below 510℃ when without Be, otherwise, below 520℃ when with Be.