【摘要】 研究了605℃服役约3万小时的Inconel 783合金螺栓，利用Thermo-calc软件对试验材料进行热力学平衡过程的模拟，研究析出相种类、组成与温度的变化趋势。对螺栓的螺纹和光杆部位进行取样研究，采用光学显微镜（OM）、扫描电镜（SEM）、透射电镜（TEM）研究合金试样的显微组织及析出相特征，并且进行布氏硬度、拉伸、冲击等力学性能测试。结果表明：螺栓光杆处的晶粒尺寸略大于螺纹处，螺纹和光杆部位的γ′及β析出相形貌、尺寸及数量大体一致。此外，γ′相主要呈纳米级小颗粒状；β相主要呈两种特征，一种尺寸比较大分布于晶内及晶界，另一种尺寸相对较小分布于晶界呈网状。同时，在β相内发现γ′相及Heusler-Ni₂AlX相的析出。试验螺栓螺纹处的硬度值高于光杆处，螺纹处的屈服强度均略高于光杆处，但高温下光杆处的断后伸长率和断面收缩率却稍高于螺纹处。更多还原

【Abstract】 Inconel 783 superalloy bolts after about 30 000 h service at 605 ℃ were studied, and the thermodynamic equilibrium process of the tested material was simulated using Thermo-calc software to study the trends of precipitated phase types and compositions with respect to temperature. The microstructure and precipitated phase characteristics of the specimens, sampled from the thread and polished rod parts of the bolts, were investigated by means of optical metallographic microscope（OM）, scanning electron microscope（SEM） and transmission electron microscope（TEM）, and the mechanical properties such as Brinell hardness, tensile and impact tests were tested. The results show that the grain size at the polished rod of the bolt is slightly larger than that at the thread, and the morphology, size and quantity of γ′ and β precipitates at the thread and polished rod are roughly the same. In addition, the γ′ phase is mainly nano-sized particles. The β phase is mainly characterized by two features, one is relatively large in size and distributed in the grain and grain boundary, and the other is relatively small in size and distributed in the grain boundary as a network. At the same time, the precipitation of γ′ phase and Heusler-Ni₂AlX phase is found in the β phase. The hardness value at the thread of the bolt is higher than that at the polished rod, and the yield strength at the thread is slightly higher than that at the polished rod, but the elongation and reduction of area at the polished rod tested at high temperature are slightly higher than those at the thread.更多还原