IN 738 LC microstructure optimization with heat treatment and simulation to improve mechanical properties of turbine blades

Download
index.pdf
2018
Boyraz, Mustafa Tarık
Show full item record
463
views
233
downloads
IN 738 LC is a Ni-based superalloy that is employed mostly in nozzle guide vanes and turbine blades in gas turbines. In these parts of gas turbines, material is exposed to high temperatures and the highly corrosive environment. Therefore, improvement in high temperature strength (yield strength, creep strength, tensile strength) and corrosion resistance are extremely important. In this study, effect of heat treatment and aluminide coating parameters to IN 738 LC microstructure were investigated. Both experimental and simulation studies were performed to improve materials microstructure and optimize its yield strength. Microstructure evolution during heat treatments and aluminide coating was simulated using JMAT PRO software and simulation results were compared to experimental results. The experimental microstructure information obtained from aluminide coating and heat treatment results were used as input to a physical model that was formed to estimate yield strength of IN 738 LC samples with different microstructures. The result of this model was compared with experimental tensile test literature findings and JMAT PRO yield strength estimations. Additionally, surface growth and diffusion during the aluminide coating were simulated using DICTRA software. The composition profile and coating thickness results of simulations were compared to experimental aluminide coating results. The purpose was to achieve a simulation model capable of estimating coating composition profile and thickness for given experimental conditions since experimental aluminide coating is a costly and time-consuming process.
Aluminum coatings., Aluminum alloys., Microstructure., Gas-turbines., Blades.
http://etd.lib.metu.edu.tr/upload/12622106/index.pdf
https://hdl.handle.net/11511/27302
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

The Influence of cooling configuration and tip geometry on gas turbine blade tip leakage flow and heat transfer
Sakaoğlu, Sergen; Kahveci, Harika Senem; Department of Aerospace Engineering (2019)
In gas turbine engines, an increase in the thermal efficiency and power output can be ensured by increasing the turbine inlet temperature. This causes the high-pressure turbine (HPT) blades to be exposed to extremely high temperatures that requires the introduction of cooling flow in order to keep the temperatures within the allowable material limits and to reduce the high thermal loads on the blade. However, cooling flow introduced around the blade tip region affects the blade tip leakage flow and blade tip he...
Effect of welding parameters on the hot cracking behavior of 7039 aluminum - zinc alloy
Akkuş, Mert; Gürbüz, Rıza; Batıgün, Caner; Department of Metallurgical and Materials Engineering (2010)
7039 aluminum alloys are widely being used in the aerospace, automotive and defense industries in which welding technique is used for their joining. The main problem encountered during the welding of 7039 aluminum alloy is hot cracking. The aim of this study is to understand the effect of welding parameters on the hot cracking behavior of 7039 aluminum alloy by using Modified Varestraint Test (MVT) with Gas Tunsgten Arc Welding (GTAW) technique. During tests, welding speed was selected as varying parameter,...
Investigation of the effect of bending twisting coupling on the loads in wind turbines with superelement blade definition
Gozcu, M. O.; Kayran, Altan (2014-01-01)
Bending-twisting coupling in the composite blades is exploited for load alleviation in the whole turbine system. For the purpose of the study, inverse design of a reference blade is performed such that sectional beam properties of the 3D blade design approximately match the sectional beam properties of NREL's 5MW turbine blade. In order to appropriately account for the bending-twisting coupling effect, dynamic superelement of the blade is created and introduced into the multi-body dynamic model of the wind ...
Production and development of aluminide coatings by chemical vapor deposition on nickel based superalloys for turbine engine applications
Ertürk, Umutcan; İmer, Muhsine Bilge; Department of Metallurgical and Materials Engineering (2017)
Diffusion coatings including aluminide coatings are utilized to improve the high temperature oxidation and corrosion resistance of turbine blades. Through the advancement in the aluminizing methods, higher purity and more homogeneously distributed coatings have been realized. The chemical vapor deposition (CVD) is the most advanced technique utilized for aluminizing process. The versatility of CVD provides a large possibility to control process variables such as temperature, pressure, gas flows and ratios, ...
Simulation of a non-premixed swirl burner
Solmaz, Mehmet Burak; Uzol, Oğuz; Uslu, Sıtkı; Department of Aerospace Engineering (2014)
Flame stabilizing in a gas turbine combustion chamber is one of the designing issues. Non-premixed swirling flames are commonly applied to aerial vehicles’ combustors due to their advantages in flame stabilizing and flame length shortening. However, swirling flows are very complex and hard to simulate even without reaction. Previous studies have showed that Large Eddy Simulation (LES) is able to predict swirling flow with a good degree of accuracy. On the other, it is quite expensive and is still far away f...
Citation Formats
M. T. Boyraz, “IN 738 LC microstructure optimization with heat treatment and simulation to improve mechanical properties of turbine blades,” M.S. - Master of Science, Middle East Technical University, 2018.
METU IIS - Integrated Information Service open@metu.edu.tr