(江蘇大學 材料科學與工程學院，鎮(zhèn)江 212013)
摘 要: 在冷金屬過渡(CMT)焊接5A66鋁合金的基礎(chǔ)上，分別添加Ti粉和Ti、Zr混合粉末進行原位合金化焊接，研究原位合金化焊接方法對焊接接頭的影響。采用光學顯微鏡(OM)、掃描電鏡(SEM)、能譜分析(EDS)、微區(qū) X射線(XRD)以及顯微硬度和拉伸力學性能測試對不同工藝條件下的試樣進行顯微組織和力學性能分析。結(jié)果表明：Ti、Zr在液態(tài)熔池中與Al反應，生成細小的Al3Ti、Al3Zr粒子，提高焊縫區(qū)的顯微硬度，但焊縫中氣孔增多。熔合線附近靠母材側(cè)存在等軸晶薄層，原位反應增加等軸晶薄層的寬度。新生成第二相顆粒的彌散強化作用提高焊縫區(qū)的力學性能。合金元素的添加對焊接接頭熱影響區(qū)的影響不大，由于實際熱輸入量很低，焊縫強度系數(shù)約為0.9。
關(guān)鍵字: 鋁合金；冷金屬過渡；焊接；Ti；Zr
（School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China）
Abstract:In order to study the effect of in-situ alloying welding on aluminum alloy joint, the cold metal transfer (CMT) in-situ welding test with the addition of Ti, Ti and Zr mixed powder was carried out on 5A66 aluminum alloy. The microstructures and mechanical properties were investigated by OM, SEM, EDS, micro X-ray diffraction, microhardness test and tensile mechanical properties test. The results indicate that, small and uniformed Al3Ti and Al3Zr particles form in the weld zone, which enhances the mechanical properties and phase distribution in this area, but this also increases the tendency of gas bubbles in the joint at the same time. There is also a grain zone along the fusion line, in-situ reaction increases the width of the grain zone. The dispersion of newly formed second phases enhances the mechanical properties of the weld seam. The alloy element addition does not affect the heat affected zone (HAZ), the strength coefficient of joints fractured is about 0.9 because of the lower heat input of CMT method.
Key words: aluminum alloy; cold metal transfer; welding; Ti; Zr
