【摘要】 一种低Re二代镍基单晶高温合金经标准热处理(1275℃×2 h+1290℃×2 h+1310℃×10 h+1315℃×8 h,空冷+1100℃×4 h空冷+870℃×20 h空冷)后，在1050℃保温50、100、200、500、1000 h长期时效处理，利用场发射扫描电镜分析合金长期时效过程中的组织演化，并在1038℃/172 MPa条件下对不同状态合金进行持久性能测试，分析长期时效对该合金持久性能的影响规律。结果表明：标准热处理后，合金具有规则立方状的γ′相；在1050℃长期时效过程中，γ′相尺寸逐渐增大，γ′相不断合并和连接，500 h时效后γ′相开始出现形筏现象，1000 h时效后未析出TCP有害相。200 h时效后合金的持久寿命大于标准热处理态合金，500、1000 h长期时效合金的持久寿命逐渐降低，这是由于标准热处理态和长期时效态合金持久变形过程中均形成了界面位错网，时效200 h后界面位错网密度升高，时效1000 h后界面位错网密度降低。更多还原

【Abstract】 A low-Re nickel-based single crystal superalloy was subjected to long-term aging treatment at 1050 ℃ for 50, 100, 200, 500 and 1000 h after standard heat treatment(1275 ℃×2 h+1290 ℃×2 h+1310 ℃×10 h+1315 ℃×8 h, AC+1100 ℃×4 h, AC+870 ℃×20 h, AC). Scanning electron microscope(SEM) was used to observe the microstructure of the alloy after standard heat treatment and long-term aging for different time. The creep rupture properties of the alloy after standard heat treatment and long-term aging were tested under the condition of 1038 ℃/172 MPa. The effect mechanism of long-term aging on the creep rupture lives of the alloy was investigated. The results show that the regular cubic γ′ phase structure is obtained after standard heat treatment. During long-term aging at 1050 ℃, the size of γ′ phase gradually increases, and γ′ phase merges and connects, even rafts after long-term aging for 500 h. Until aging for 1000 h, the TCP phase is not precipitated in the alloy. The creep rupture life of the alloy after long-term aging for 200 h is longer than that of the standard heat treated, and then the creep rupture lives of the alloy aged for 500 h and 1000 h gradually decrease. This is due to interfacial dislocation networks formed in the standard heat treated and long-term aged alloy during creep rupture tests. The interfacial dislocation networks increase after aging for 200 h, while then decrease after aging for 1000 h.更多还原