The optimal composition of a metal alloy for use in the construction of a high-temperature turbine blade for aerospace applications is typically a nickel-based superalloy. One such example is Inconel 718, which consists of approximately 50-55% nickel, 17-21% chromium, 4.75-5.5% niobium, 2.8-3.3% molybdenum, 1% titanium, 0.35-0.8% aluminum, and other minor elements.The properties of this alloy that contribute to its superior performance under high-temperature conditions include:1. High-temperature strength: Nickel-based superalloys have excellent strength and resistance to deformation at high temperatures, which is crucial for turbine blades that operate under extreme heat and stress.2. Oxidation and corrosion resistance: The presence of chromium in the alloy provides excellent resistance to oxidation and corrosion, which is essential for components exposed to high-temperature combustion gases.3. Creep resistance: The addition of elements like niobium, molybdenum, and titanium enhances the alloy's resistance to creep, which is the slow deformation of materials under constant stress at high temperatures. Creep resistance is crucial for maintaining the structural integrity of turbine blades over time.4. Thermal fatigue resistance: Nickel-based superalloys have excellent resistance to thermal fatigue, which is the damage caused by repeated cycles of heating and cooling. This property is essential for turbine blades that experience rapid temperature changes during operation.5. Coefficient of thermal expansion: The alloy's coefficient of thermal expansion is well-matched to the surrounding materials, reducing the risk of thermal stresses and distortion during operation.Overall, the optimal composition of a metal alloy for high-temperature turbine blades in aerospace applications is a nickel-based superalloy, such as Inconel 718, due to its excellent high-temperature strength, oxidation and corrosion resistance, creep resistance, thermal fatigue resistance, and suitable coefficient of thermal expansion.