Zhu Qiang, Chen Gang, Wang Chuanjie, Qin Heyong, Zhang Peng
Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin 150080, China.
School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209, China.
Materials (Basel). 2019 Aug 2;12(15):2461. doi: 10.3390/ma12152461.
Nickel-based superalloys have become key materials for turbine disks and other aerospace components due to their excellent mechanical properties at high temperatures. Mechanical properties of nickel-based superalloys are closely related to their microstructures. Various heat treatment processes were conducted to obtain the desired microstructures of a nickel-based superalloy in this study. The effect of the initial microstructures on the tensile deformation and fracture behaviors was investigated via in situ digital image correlation (DIC) and synchrotron radiation X-ray tomography (SRXT). The results showed that the size and volume fraction of γ″ and γ' phases increased with the aging time. The yield strength and the ultimate tensile strength increased due to the precipitation strengthening at the expense of ductility. The surface strain analysis showed severely inhomogeneous deformation. The local strains at the edge of specimens were corresponded to higher void densities. The fracture of carbides occurred owing to the stress concentration, which was caused by the dislocation accumulation. The fracture mode was dimple coalescence ductile fracture.
镍基高温合金因其在高温下优异的力学性能，已成为涡轮盘和其他航空航天部件的关键材料。镍基高温合金的力学性能与其微观结构密切相关。本研究通过各种热处理工艺来获得一种镍基高温合金所需的微观结构。通过原位数字图像相关（DIC）和同步辐射X射线断层扫描（SRXT）研究了初始微观结构对拉伸变形和断裂行为的影响。结果表明，γ″相和γ′相的尺寸和体积分数随时效时间增加。屈服强度和抗拉强度因沉淀强化而提高，但以韧性为代价。表面应变分析表明变形严重不均匀。试样边缘的局部应变对应于较高的孔隙密度。碳化物因位错堆积引起的应力集中而发生断裂。断裂模式为韧窝聚结韧性断裂。
