(南昌航空大學(xué) 航空制造與工程學(xué)院，南昌 330063)
摘 要: 對(duì)GH3044高溫合金進(jìn)行光纖激光自熔焊對(duì)接實(shí)驗(yàn)，結(jié)合OM、SEM、EDS、XRD和預(yù)拉伸變形等分析方法研究焊接接頭的焊縫形貌、組織變化特征和力學(xué)性能，討論焊縫金屬快速凝固過(guò)程中的相變及元素偏析。結(jié)果表明：熱輸入的增加會(huì)導(dǎo)致熔化的金屬量增加，熔池的Marangoni對(duì)流效應(yīng)更明顯；焊縫金屬上部和下部區(qū)域?yàn)榇执蟮闹鶢罹В胁繀^(qū)域?yàn)槌叽巛^小的柱狀晶，熔合線靠近焊縫附近區(qū)域?yàn)榧?xì)小樹(shù)枝晶，熱輸入較小時(shí)，焊縫中心區(qū)域有等軸晶生成；焊縫組織主要為γ相、共晶(γ+M6C)相，EDS分析表明合金元素的微觀偏析較弱；靠近熔合線的熱影響區(qū)組織變化較小，但焊縫、熱影響區(qū)的硬度均高于母材的；隨著熱輸入的減小，焊接接頭的硬度、抗拉強(qiáng)度逐漸增大，抗拉強(qiáng)度最大為865 MPa，伸長(zhǎng)率為43%。
關(guān)鍵字: GH3044高溫合金；激光焊接；凝固路徑；顯微組織；變形均勻性
（School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang 330063, China）
Abstract:GH3044 superalloy was welded by the fiber laser. The weld morphology, microstructure, mechanical properties and the solidification process were investigated. The results show that with the increase of heat input, the area of the cross section of the weld increases gradually. It can also be seen that the upper and lower welds are larger columnar crystals. The columnar crystal size is smaller in the middle of the weld, and the area near the fusion line is fine dendrite. Furthermore there are equiaxed grains in the center of the weld when the heat input is reduced. It is also found that the microstructure constitution of the weld is mainly γ phase, eutectic (γ+M6C) phase. EDS analysis shows that the microsegregation of the alloy elements is weak. The microstructure of the heat affected zone near the fusion line is small, but the hardness of the weld and heat affected zone is higher than that of the parent material and the joint. With the decrease of heat input, the hardness and tensile strength of the welded joint increase gradually, the tensile strength is 865 MPa, and the elongation is 43%.
Key words: GH3044 superalloy; laser welding; solidification process; microstructure; mechanical properties
