The Mar-M247 nickel-based superalloy turbine blade was investigated by tensile tests conducted from room temperature to 980 ℃. The microstructure, tensile properties, and fracture mechanisms of the alloy were analyzed. Results indicate that the alloy's microstructure primarily consists of γ phase, flower-like γ′ phase, γ/γ′ eutectic structure, and carbide phases. The alloy strength initially increases and then decreases with increasing temperatures. At low temperatures, fracture exhibits a mixed mode dominated by transgranular fracture with intergranular fracture as a secondary component, where cracks preferentially initiate at carbide/matrix interfaces. When the temperature reaches 980 ℃, the fracture mechanism transitions to microvoid coalescence-induced ductile fracture, accompanied by an increase in elongation to 6.4%. Deformation mechanism analysis reveals that stacking fault shearing dominates in the low-temperature region (<400 ℃), forming Lomer-Cottrell (L-C) dislocation locks. The intermediate temperature range (400–760 ℃) displays Portevin-Le Chatelier (PLC) effects coupled with intermediate-temperature brittleness. Above 760 ℃, widening matrix channels and increased stacking fault energy promote a synergistic interaction between antiphase boundary (APB) shearing and Orowan bypassing mechanisms, leading to a significant decrease in deformation resistance.