Al-Ni-Mg 三元共晶 合金의 方向性 凝固에 관한 연구
- Al-Ni-Mg 三元共晶 合金의 方向性 凝固에 관한 연구
- Other Titles
- A study on the directional solidification of Al-Ni-Mg ternary eutectic alloys
- Issue Date
- No. 2
- 本 實驗은 Al-Ni合金에 Mg 添加量을 0∼0.9wt%까지 變化시키면서 各種 凝固速度로 方向性 凝固를 시켰으며 方向性 凝固後 方向性 凝固組織과 機械的 性質 및 添加元素(Mg), 凝固速度의 影響을 硏究, 調査하였다. 여기서 얻은 結果를 要約하면 다음과 같다. 1) composite 組織은 凝固速度가 0.1∼0.04㎜/min 사이에서 觀察 되었으며 添加元素量이 增加할수록 보다 낮은 凝固速度에서 composite 組織이 觀察되었다. (方向性 凝固裝置의 溫度勾配는 全實驗을 통하여 80℃／㎝로 同一). 2) 金屬間 化合物의 相間幅 λ와 相形能는 凝固速度 R에 의존하며 Al-Ni 共晶合金 系에서 λ^-1=1.28×10 exp(4)√R의 直線關係 成立되었다. 3) Al-Ni系 및 Al-Ni-Mg系의 경우 鑄方狀態의 試料보다 方向性 凝固를 시킨 경우의 試料가 引張强度面에서는 상당히 增加 하였으나 延伸率 面에서는 약간 減少하였다. 4) Ageing 效果는 純 Al-Ni 系에서는 거의 없었으며 Al-Ni-Mg의 경우는 時效後가 時效前보다 引張强度가 상당히 增加하였다.
Al-Ni alloy was directionally solidified with various solidification rate in the range of Magnesium content, 0∼0.9wt%. And also the Metallurgical Structure, Mechanical Properties, the effect of additional element(Magnesium) and solidification rate of directionally solidied Al-Ni alloy were investigated. From this experiment the following results were obtained. 1) The Composite structure was observed in the range of solidification rate, 0.1∼0.04㎜/min. And also more composite structure were observed in less solidification rate according to the increment of additional element (temperature gradient 80℃／㎝). 2) The shape of phase and the rod spacing λ of intermetallic compound were depended on the solidification rate R, and also linear relationship was obtained λ^-=1.28 × 10 exp(4)√R between the square root of solidification rate, R＾(1／2) and the reciprocal of rod spacing λ＾-1. 3) In case of Al-Ni system and Al-Ni -Mg system, The Measured values of ultimate tensile strengths of directionally solidified were more increased, but the elongation was a little bit decreased than in as cast. 4) The ageing effects of directionally solidified pure Al-Ni system was almost negligible, but the ultimate tensile strength of Al-Ni-Mg system was more increased due to the ageing
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