The influence of low angle boundaries (LABs) on the tensile behavior of a third generation single crystal superalloy at temperatures of 760, 850 ℃, and 980 ℃ has been explored. The microstructure of the specimens after tensile rupture is examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The findings reveal that the third generation single crystal superalloy with LABs demonstrates favorable tensile properties. LABs with angles ranging from 0° to 8.9° have a negligible impact on the yield strength and ultimate tensile strength of the alloy at 760, 850 ℃, and 980 ℃. At 980 ℃, the tensile strength of the specimen with LABs of 11.4° decreases by 80 MPa compared to that of the specimen with LABs of 0°. As the angle of the LABs increases, the elongation of the alloy with LABs in the range of 0°-11.4° at 980 ℃ exhibits a downward trend. Additionally, the propensity for intergranular fracture in the alloy with LABs becomes more pronounced as either the angle of the LABs increases or the temperature rises.

Single crystal superalloys exhibit excellent comprehensive properties and have been widely applied in advanced aero-engines. This paper reviews the development of single crystal superalloys from the aspects of strengthening mechanism and composition design, directional solidification and crystal growth, solid-state phase transformation and heat treatment and mechanical behaviour. Special emphasis is placed on the research progress of the high-performance, low-cost single crystal superalloys with independent intellectual property rights of China developed by Beijing Institute of Aeronautical Materials, and future development direction of single crystal superalloys are discussed.