【摘要】：對Al-Cu-Li鑄態(tài)合金進行單級和雙級均勻化處理,通過光學顯微鏡(OM)、掃描電鏡(SEM)、能譜分析(EDS)、X衍射(XRD)和差熱分析(DSC)研究合金元素分布和微觀組織演化。結(jié)果表明:Al-Cu-Li合金鑄態(tài)組織存在嚴重枝晶偏析,由晶內(nèi)到晶界Cu元素分布十分不均勻,Mg、Zn、Mn和Ag變化不明顯。晶界處存在大量的非平衡共晶相,主要包括Al_2Cu、含有少量Mg元素的Al_2Cu相,以及Al_2Cu Mg相。經(jīng)雙級均勻化(495℃/24 h+515℃/_24 h)處理后,大部分非平衡共晶相和部分第二相(Al_2Cu Mg和Al_2Cu Li)溶解到合金基體,但仍有部分富-Fe和富-Mn相殘留在晶界不能回溶。Al_2Cu Mg相的熔點低于Al_2Cu相,兩者分別在495和515℃先后溶解。通過均勻化動力學分析,確定Al-Cu-Li鋁鋰合金最佳的均勻化制度為495℃/24 h+515℃/24 h,該雙級均勻化制度與動力學分析結(jié)果一致。
[Abstract]:Single stage and two stage homogenization treatment was carried out on the as-cast Al-Cu-Li alloy. The element distribution and microstructure evolution of the as-cast Al-Cu-Li alloy were studied by means of (OM), scanning electron microscope (SEM),) and differential thermal analysis (DSC), which were characterized by (EDS) X diffraction (XRD) and differential thermal analysis (DTA). The results show that there is a serious dendritic segregation in the as-cast microstructure of the alloy, and the distribution of Cu elements from the inner grain to the grain boundary is very uneven. There are no obvious changes in mn and Ag in the as-cast structure of the alloy. There are a large number of non-equilibrium eutectic phases at grain boundaries, including the Al_2Cu phase with a small amount of Mg elements in Al_2Cu, and the Al_2Cu Mg phase. After two-stage homogenization (495 鈩，

本文編號：2251030