Materials used in Turbine blades

There has been a wide range of materials used for the manufacturing of gas turbine blades. It is one of the most important parts in a gas turbine and any deterioration of it will affect the performance and efficiency of the turbine and most importantly will damage the turbine.

 Many materials have been tested and used but the most preferred materials include steel, titanium, Nickel based super alloys and ceramics. The first stage of the compressor is very delicate as it is subjected to a very high temperature of approx. 1400-1500 degree celsius. 

This part of the turbine should tolerate high temperatures, high pressures, high thermal stresses including creep and fatigue, vibrations which can influence it's performance. The first stage uses Udimet 500, Nickel based super alloy Inconel 738 or GTD 111. 

The relatively cold stages of the turbine employ titanium as there are chances of it igniting when used above 500 degree celsius. 

      Applications                             Oxidation   Hot corrosion    Interdiffusion    Thermal Fatigue                            Aircraft                           Severe         Moderate             Severe                 Severe                     Land-based Power Generator       Moderate        Severe              Moderate                Light                     Marine Engines                            Moderate        Severe                Light                 Moderate

Nickel alloys with a mixture of Chromium, Cobalt and Rhenium are preferably used. However there is a high risk of corossion, oxidation or even the attack of the metal directly. For this purpose a ceramic based coating is used since ceramics can withstand temperatures above 2000 degree celsius.

Coating turbine blades

 The nature of coating must be selected such that it ha low thermal conductivity to minimize the heat transfer to the base metal.It should also be porous and hence Yttria stabilized Zirconia is applied.

 It is not necessary that we limit ourselves to the above mentioned materials. Different materials can be tested and employed with the main aim of increasing the endurance and performance of the blades.