中文摘要：

IN718合金具有优异的高温力学性能和良好的加工性,广泛地用于航空发动机涡轮盘、压气机盘、动力传动轴等转动部件。IN718合金的力学性能,特别是蠕变和疲劳性能是决定发动机安全性和可靠性的关键因素。利用光学显微镜（OM）,扫描电镜（SEM）,电子背散射（EBSD）等方法系统地研究了固溶处理（温度范围从900℃到1050℃）对该合金显微组织和力学性能,包括室温和650℃拉伸、650℃/700 MPa持久、450℃低周疲劳的影响。结果显示,固溶温度从900℃到990℃,？相的体积分数随温度的升高而降低,晶粒尺寸保持不变。固溶温度从990℃到1050℃,？相完全回溶,晶粒尺寸从15μm长大到100μm。通过调整IN718合金的显微组织,可以满足航空、石化、能源等不同工业领域对材料耐高温、耐腐蚀、抗辐射的使用要求。

英文摘要：

IN718 alloy exhibits excellent mechanical properties at high-temperature and good workability,which has been widely used in aircraft engine turbine disks,compressor disks,and power turbine shafts（i.e. rotating components）. The mechanical properties of IN718 alloy,especially its creep and fatigue properties are a key factor determining the safety and reliability of engines. In this study,the effects of solution treatment at temperature ranging from 900 ℃ to 1050 ℃ on the microstructure and mechanical properties（including the tensile strength at room temperature and 650 ℃,the stress-rupture behavior at 650 ℃ and 700 MPa,and the low-cycle fatigue behavior at 450 ℃） were investigated by optical microscopy（OM）,scanning electron microscopy（SEM） and electron backscatter diffraction（EBSD）. The results show that in specimens subjected to solution treatment at temperature from 900 ℃ to 990 ℃,the mass fraction of the ζ-phase decreases with increasing temperature,whereas the grain size remains the same. However,in specimens treated at temperature ranging from 990 ℃ to 1050 ℃,the ζ-phase is dissolved and the grain size increases from 15 μm to 100 μm. With proper adjustment of the microstructure of IN718 alloy,this material can satisfy the requirements for high-temperature,corrosion-resistance,and radiation-tolerance,such as the aviation,petrochemical,and nuclear power industries.