A turbine blade is a radial aerofoil mounted in the rim of a turbine disc and which produces a tangential force which rotates a turbine rotor. Each turbine disc has many blades. As such they are used in gas turbine engines and steam turbines. The blades are responsible for extracting energy from the high temperature, high pressure gas produced by the combustor. The turbine blades are often the limiting component of gas turbines. To survive in this difficult environment, turbine blades often use exotic materials like superalloys and many different methods of cooling that can be categorized as internal and external cooling, and thermal barrier coatings. Blade fatigue is a major source of failure in steam turbines and gas turbines. Fatigue is caused by the stress induced by vibration and resonance within the operating range of machinery. To protect blades from these high dynamic stresses, friction dampers are used.

Blades of wind turbines and water turbines are designed to operate in different conditions, which typically involve lower rotational speeds and temperatures.

In a gas turbine engine, a single turbine stage is made up of a rotating disk that holds many turbine blades and a stationary ring of nozzle guide vanes in front of the blades. The turbine is connected to a compressor using a shaft (the complete rotating assembly sometimes called a "spool"). Air is compressed, raising the pressure and temperature, as it passes through the compressor. The temperature is then increased by combustion of fuel inside the combustor which is located between the compressor and the turbine. The high-temperature, high-pressure gas then passes through the turbine. The turbine stages extract energy from this flow, lowering the pressure and temperature of the gas and transfer the kinetic energy to the compressor. The way the turbine works is similar to how the compressor works, only in reverse, in so far as energy exchange between the gas and the machine is concerned, for example. There is a direct relationship between how much the gas temperature changes (increase in compressor, decrease in turbine) and the shaft power input (compressor) or output (turbine).

For a turbofan engine the number of turbine stages required to drive the fan increases with the bypass-ratio unless the turbine speed can be increased by adding a gearbox between the turbine and fan in which case fewer stages are required. The number of turbine stages can have a great effect on how the turbine blades are designed for each stage. Many gas turbine engines are twin-spool designs, meaning that there is a high-pressure spool and a low-pressure spool. Other gas turbines use three spools, adding an intermediate-pressure spool between the high- and low-pressure spool. The high-pressure turbine is exposed to the hottest, highest-pressure air, and the low-pressure turbine is subjected to cooler, lower-pressure air. The difference in conditions leads to the design of high-pressure and low-pressure turbine blades that are significantly different in material and cooling choices even though the aerodynamic and thermodynamic principles are the same. Under these severe operating conditions inside the gas and steam turbines, the blades face high temperature, high stresses, and potentially high vibrations. Steam turbine blades are critical components in power plants which convert the linear motion of high-temperature and high-pressure steam flowing down a pressure gradient into a rotary motion of the turbine shaft.

Turbine blades are subjected to very strenuous environments inside a gas turbine. They face high temperatures, high stresses, and a potential environment of high vibration. All three of these factors can lead to blade failures, potentially destroying the engine, therefore turbine blades are carefully designed to resist these conditions.

Turbine blades are subjected to stress from centrifugal force (turbine stages can rotate at tens of thousands of revolutions per minute (RPM)) and fluid forces that can cause fracture, yielding, or creep failures. Additionally, the first stage (the stage directly following the combustor) of a modern gas turbine faces temperatures around 2,500 °F (1,370 °C), up from temperatures around 1,500 °F (820 °C) in early gas turbines. Modern military jet engines, like the Snecma M88, can see turbine temperatures of 2,900 °F (1,590 °C). Those high temperatures can weaken the blades and make them more susceptible to creep failures. The high temperatures can also make the blades susceptible to corrosion failures. Finally, vibrations from the engine and the turbine itself can cause fatigue failures.

Higher temperatures lead to better cycle efficiency in a turbine, calling for a need for materials innovation that continually pushes the previous benchmark. As the most common modes of failure in SC and polycrystalline blades are intrinsically different, SC blades, thanks to their lack of grain boundaries, are ideal for first and second stage turbine blade applications. Turbine blades are typically made of Ni-Cr superalloys, which present a unique microstructure.

Single crystal (SC) superalloys are typically cast with the ⟨001⟩ crystallographic direction along the turbine blade's axis, and often with a controlled secondary orientation, which has been found to be ideal for reducing localized stresses. Their microstructure consists of cuboidal γ′ precipitates aligned along ⟨001⟩ within a γ matrix. These alloys exhibit anisotropic mechanical properties due to the FCC structures of γ and γ′, also known as orthotropic properties. These include tensile and creep properties, which are also influenced by temperature alloy composition. This anisotropy strongly affects deformation and damage during thermo-mechanical fatigue (TMF).