Study of the Microstructure of the Gas Turbine Internal Blade

High Pressure Turbine (HPT) first stage blade is the most important rotational
components of aero-engine. It operatesat high temperature and under conditions of
extreme environmental attack such as oxidation and corrosion, isespecially subjected to
degradation by oxidation, corrosion and wear. Due to the elevated temperature been
introduced on the turbine blades, they faced several failure such as thermal stress failure
and creep. This failure is very common and always occurred on this life limiting
component of gas turbine. Further study on the microstructure behavior with respect to
the temperature along the blade is carried out to predict the cycle life of the blade.
The objective of this project is basically to study on the microstructure of Nickel based
Superalloy characterization. The study is mainly focusing on the evaluation of the
morphology changeof the γ′particles, carbide precipitation and characterization of
particle type and size.Then, a complete procedure and testing related with the study of
gas turbine blades were performed using relevant equipment and tools.The procedure
involves preparing metallographic sample, chemical analysis and analyzing the
microstructure under FESEM and EDS. Though, the main objective of this project is to
create a complete profile of microstructure along the turbine blade. This profile is
believed to be very useful in the industry to predict the cycle life of turbine blade.
Thorough analysis been done,the microstructure undergoes transformations which likely
degrade the mechanical properties of the alloy, including γ’ coarsening, increased
carbide precipitation in grain boundaries, andincreasinggrain size with respect to
temperature. From the analysis, we can predict the temperature profile alongside the
blade, which is increase from lower part to upper part. Therefore, the operating
temperature of gas turbine need to be maintain so that the microstructure of blade is not
affected and as well reduce the lifespan of turbine blade.