(湖南大學(xué) 汽車車身先進(jìn)設(shè)計制造國家重點實驗室，長沙 410082)
摘 要: 采用光纖激光器對1.4 mm厚DC51D+ZF鍍鋅鋼和1.2 mm厚6016鋁合金平板試件進(jìn)行添加Mn、Zr粉末的激光搭接焊試驗，利用金相顯微鏡、顯微硬度儀、掃描電鏡、X射線衍射儀、微機控制電子萬能試驗機等研究焊接接頭各區(qū)域的金相組織、顯微硬度、斷口形貌、主要物相與接頭的力學(xué)性能。結(jié)果表明：在鋼/鋁激光焊中添加Mn、Zr粉末，焊接接頭平均抗剪強度與沒有添加粉末相比，有所提高，其中添加Zr粉末的提高效果明顯；Mn、Zr粉末的添加改變了鋼/鋁界面的元素分布、物相組成及微觀組織形態(tài)，添加Mn能提高熔池金屬的流動性，利于鋼/鋁界面結(jié)合，而添加Zr，焊縫區(qū)晶粒細(xì)小，形成新的ZrFe3.3Al1.3韌性相，抑制Fe-Al脆性金屬間化合物生成。因此，添加Mn、Zr均改善了鋼/鋁焊接接頭的力學(xué)性能。
關(guān)鍵字: 激光焊接；異種金屬；金屬間化合物；微觀組織；力學(xué)性能
（State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body,
Hunan University, Changsha 410082, China）
Abstract:The fiber laser welding test with Mn and Zr powder addition was carried out on the DC51D+ ZF galvanized steel with thickness of 1.4 mm and the 6016 aluminum alloy with thickness of 1.2 mm. By using optical microscopy, electron microscopic hardness, scanning electron microscopy, X-ray diffraction and the tensile test, the microstructure, hardness, mechanical properties of joints, fracture morphology and the main phase of the welded joint region were studied. The results indicate that when Mn, Zr powders are added in steel/aluminum, the average shear strength of the welding sample is improved compared with that without power addition, and Zr is considered as the best power based on improved mechanical properties of joints. The element distribution, phase composition and microstructure of the steel/aluminum interface are changed due to Mn and Zr powders addition. When Mn powder is added in steel/aluminum, the fluidity of the molten pool metal is improved, which promotes the combination of the steel/aluminum interface, when Zr powder is added in steel/aluminum, fine grain is seen, and a new ductile intermetallic compound ZrFe3.3Al1.3 inhibits the generation of intermetallic compounds of Fe-Al, which can improve the mechanical properties of weld metal with Mn and Zr powder addition.
Key words: laser welding; dissimilar metal; intermetallic compound; microstructure; mechanical properties
