冷却速率、保温时间对DD3单晶合金TLP连接接头组织和性能的影响  

Effects of Cooling Rate and Holding Time on Microstructure and Property of TLP Bonded Joints for DD3 Single Crystal Superalloy

作　　者：李晓红[1,2] 叶雷[1] 钟群鹏[2] 曹春晓[1] 毛唯[1] 

机构地区：[1]北京航空材料研究院,北京100095 [2]北京航空航天大学,北京100191

出　　处：《航空材料学报》2015年第1期1-7,共7页Journal of Aeronautical Materials

摘　　要：对DD3单晶合金进行1250℃保温不同时间的TLP扩散连接研究。降温过程采取了随炉冷却和充氩快冷两种方式,随后对接头进行了870℃/32h/空冷的时效处理。分析了不同规范下的焊缝及母材的组织,同时测定了接头的980℃持久性能。结果发现:炉冷并时效处理试样的焊缝及母材中的γ'相的尺寸随着保温时间增加而增加,且形状趋于不规则。而充氩冷却并时效处理试样的焊缝及母材中的γ'相的尺寸和形状基本一致,随保温时间的增加没有明显变化,立方化较好。低的冷却速率使焊缝和母材中的γ'相粗化从而降低了接头和母材的性能,而高的冷却速率促使焊缝及母材中形成细小立方化的γ'相,不仅使接头性能明显提高,同时母材性能也没有降低。Transient liquid phase （TLP） bonding of DD3 single crystal superalloy at 1250℃ with different holding time was studied. Two cooling methods such as furnace-cooling （FC） and Ar-quench cooling （AC） were adopted. An aging treatment with 870℃/32h/ air cooling was performed after the welding process. Microstructures of bonding seams and base metals with different welding conditions were observed and stress-rupture properties at 980℃ of the joints were tested. The results show that the size of γ＇phases of bonding seams and base metals by FC increases with holding time, and the shape becomes irregular. While when AC method is used, the size and shape of γ＇phases are not changed with holding time and γ＇phases are still fine and cube-like. Low cooling rate makes γ＇phases of welding seams and base metals become bigger, which leads to the deterioration of mechanical properties of the joints and base metals. On the other hand, high cooling rate makes fine and cube-like γ＇phases, which increases the mechanical property of the joints, and en- sures the property of the base metal is maintained.

关 键 词：单晶高温合金 过渡液相扩散焊 冷却速率 高温持久性能 

分 类 号：TG146.15[一般工业技术—材料科学与工程] V261.34[金属学及工艺—金属材料]