保溫時間對K452高溫合金釬焊接頭組織與性能的影響Effect of Holding Time on Microstructure and Mechanical Properties of K452 Superalloy Brazed Joints

采用鈷基釬料及鎳基合金粉料,分別在1170℃保溫10min、60min和120min的釬焊工藝下,對K452鎳基鑄造高溫合金進行真空釬焊實驗,通過掃描電鏡和能譜分析儀進行了接頭顯微組織觀察與物相分析,并測試釬焊接頭的高溫力學(xué)性能。結(jié)果表明:在保溫60min的工藝規(guī)范下,界面實現(xiàn)較好的結(jié)合,釬縫內(nèi)部孔洞缺陷較少,釬縫組織均勻,有利于釬焊接頭性能的提高;在更長的保溫時間120min下,釬縫內(nèi)部又有蝕孔缺陷形成,且較多的白色塊狀化合物在合金粉顆粒間聚集長大,但界面結(jié)合良好,釬焊接頭性能較高,900℃抗拉強度達到400MPa,900℃/100MPa持久壽命為141h55min。

Vacuum brazing of K452 superalloy was performed with cobalt-base filler metal and nickel-base superalloy powder under brazing conditions of 1170℃/10min, 1170℃/60min and 1170℃/120min respectively. The microstructure of brazed joints was analyzed by using SEM and EDS, and the high-temperature mechanical properties were also studied. The results show that the sound joints with fine microstructure and rare pores are achieved under 1170℃/60min brazing procedure, due to the good quality of interface. The joints braze under 1170℃/120min show the highest mechanical properties because of better interface quality, the average 900℃ tensile strength of 400MPa and 900℃/100MPa stress-rupture life of 141h/55min. But there morepoles are presented, and many white particles of compound congregated and grow up between the nickel-base superalloy powder in the brazing seam.