壓鑄A380鋁合金之延性改善

Improving the Ductility of A380 Die Casting Al Alloy

鄭仲凱(C. K. Cheng) ； 許哲維(C. W. Hsu) ； 許友儒(Y. J. Hsu) ； 楊智富(C. F. Yang) ； 陳俊沐(C. M. Chen) ； 邱垂泓(C. H. Chiu) ； 曾發培(F. P. Tseng)

《鑄造工程學刊》 42卷3期 (2016/09) Pp. 7-18

摘要

輕量且尺寸精密之A380壓鑄鋁合金被大量使用於運輸及3C產業(電腦、通訊及消費電子)，但因其脆性而難以作為承載較大應力或衝擊力之結構件。A380壓鑄鋁合金鑄件延伸率不足的原因主要來自鑄件內部之脆相，這些脆相包括共晶層狀組織內之共晶Si，以及鑄件冷凝時所產生的β-Al5FeSi富鐵相與Al2Cu(Mg)晶出相等；針對此問題，本研究共製備五種A380系列鋁合金，探討以合金成分微調來改變脆相組織及其含量，包括：藉由添加微量Sr(調質劑)對A380鋁合金之片狀共晶Si予以纖維化，降低合金之Fe含量及添加Mn、Cr(中和劑)來減少及轉換脆性之富鐵相之數量及型貌，降低合金之Cu含量或去除合金之Mg元素以減少或轉換S-Al2Cu(Mg)晶出相之數量及型貌，使A380鋁合金之延伸率獲得有效改善。實驗結果顯示，比起鑄造狀態之壓鑄A380鋁合金(延伸率為4.6%)，經成分微調之鑄態A380-1壓鑄鋁合金之延伸率達到8.1%；而不含Mg之元素之A380-4鋁合金之延伸率可達到9.1%。

關鍵字

A380壓鑄鋁合金 ； 延伸率 ； 共晶矽 ； 富鐵相

並列摘要

Light weight die cast A380 Al alloy products with precision dimensions have been used extensively in transportation and 3C (computer, communication and consumer electronics) industries. However, their applications as structural components are limited in areas where a major or impact loading is applied. The reason why die casting A380 Al alloy products normally show poor elongation is because the castings normally contain a variety of brittle phases, including eutectic Si, β-Al_5FeSi and Al_2Cu(Mg) phases. As such, a series of five A380 base alloys, namely A380 and A380-1 to A380-4, was made for the study of alloying effects on the brittle phases in the alloys. This was conducted by adding a small amount of Sr to the A380 alloy to modify the morphology of eutectic Si, reducing the amount of Fe and adding Mn or Cr to modify the the amount and the morphology of β-Al5FeSi, and decreasing the amount of Cu and Mg to modify the amount and the compound structure of Al_2Cu(Mg) phase. The results showed that, the modified A380-1 alloy with composite-adjustment in alloying elements show a great improvement in ductility of 8.1%, as compared to the A380 alloy of 4.6%. And the modified Mg-free A380-4 alloys exhibits the highest ductility of 9.1%.

並列關鍵字

die cast A380 Al alloy ； elongation ； eutectic Si ； Al5FeSi