(鋼鐵研究總院 先進(jìn)鋼鐵流程及材料國家重點(diǎn)實(shí)驗(yàn)室，北京100081)
摘 要: 在ER2319焊絲的基礎(chǔ)上，分別添加少量Ce、Cr及Mn元素制備了3種焊絲。采用光學(xué)顯微鏡、掃描電鏡和能譜分析技術(shù)研究微量元素Ce、Cr和Mn對(duì)MIG焊縫組織和性能的影響。結(jié)果表明：Ce能夠細(xì)化二次枝晶間距，但Ce易與Ti、Zr相互反應(yīng)在晶界生成塊狀硬而脆的AlCuCeTiZrV復(fù)雜金屬間化合物，降低了Ti和Zr的異質(zhì)形核作用，使焊縫組織成柱態(tài)。而Cr和Mn則能促進(jìn)Al3Ti、Al3Zr以及復(fù)合析出物Al3(Zr, Ti)的析出，增加這些顆粒在高溫條件下的穩(wěn)定性，能夠顯著細(xì)化焊縫晶粒和晶界共晶相，提升接頭的力學(xué)性能。但Mn的含量達(dá)到0.58%時(shí)，焊縫中心容易形成粗大樹枝晶。
關(guān)鍵字: 高強(qiáng)鋁合金；微量元素；形核；等軸晶
（State Key Laboratory of Advanced Steel Processes and Products, Centre Iron & Steel Research Institute, Beijing 100081, China）
Abstract:On the basis of ER2319 filler wire, three filler wires were prepared by adding Ce, Cr and Mn elements. The effects of these trace elements on the microstructure and mechanical properties of MIG welds were investigated by optical microscopy, scanning electron microscopy and energy dispersive spectrum. The results indicate that the addition of Ce can refine the second dendrite arm spacing, but it is easy to form AlCuCeTiZrV complex intermetallic compound at the grain boundary, which will reduce the refinement efficiency of the Ti and Zr inoculants, and make the morphology of the welds microstructure to be columnar. Cr and Mn are proved to improve the refinement efficiency of the Ti and Zr inoculants by increasing the precipitation of Al3Ti, Al3Zr and Al3(Zr, Ti) particles and the stability of these particles under high temperature conditions, which will result in the finer grains and eutectic phase in weld centre and the higher mechanical properties of the welds. When the amount of Mn is 0.58%(mass fraction), the coarse dendrite grains form in the weld centre.
Key words: high strength aluminum alloy; trace elements; nucleation; equiaxed grain
