Braze Repair of MA754 Aero Gas Turbine Engine Nozzles

1989 ◽  
Author(s):  
J. E. Elder ◽  
R. Thamburaj ◽  
P. C. Patnaik
Keyword(s):  
Fatigue Cracks ◽  
Oxide Dispersion Strengthened ◽  
Experimental Program ◽  
Nickel Base Superalloy ◽  
Turbine Engine ◽  
Repair Procedure ◽  
Brazed Joints ◽  
Nickel Base ◽  
Thermal Fatigue Cracks ◽  
Base Superalloy

MA754, an oxide-dispersion strengthened nickel-base superalloy, is the vane material being used in the High Pressure Turbine (HPT) Nozzle of the F404-400 turbofan engine. Thermal fatigue cracks are known to develop in the nozzle vanes during service and the component replacement costs can, in general, be very high. Attempts to demonstrate the feasiblity for braze repair of MA754 have thus far yielded little success. An experimental program aimed at developing a braze repair procedure for healing cracks in MA754 HPT nozzles is described. Thirteen different braze compositions, using two different brazing times and gap widths, are evaluated. Experimental results are described detailing the microstructure, degree of oxide agglomeration and porosity in the region of the brazed joints. The feasibility of applying a braze repair procedure to the nozzle component is discussed.

Improvement of Thermal Fatigue Resistance of A Wrought Nickel-Base Superalloy by Laserglaze

1985 ◽  
Vol 58 ◽  
Author(s):  
Zhao Qi ◽  
Ge Yunlong ◽  
Hu Zhuangqi ◽  
Jiang Ming ◽  
Shih Changshu
Keyword(s):  
Heat Treatment ◽  
Fatigue Resistance ◽  
Thermal Fatigue ◽  
Fatigue Cracks ◽  
Nickel Base Superalloy ◽  
Post Heat Treatment ◽  
Thermal Fatigue Resistance ◽  
Nickel Base ◽  
Thermal Fatigue Cracks ◽  
Base Superalloy

ABSTRACTLaserglaze with appropriate post heat treatment has improved the thermal fatigue resistance of a wrought nickel-base superalloy. It was found that laserglaze was able to eliminate the blocky MC phase, refine grains and form a very interesting microstructure of serrated grain boundaries. Careful selection of post heat treatment markedly increased the strength in the laser irradiated region. The initiation and propagation of thermal fatigue cracks were suppressed by this novel microstructure.

Thermo-Mechanical Fatigue of the Nickel Base Superalloy IN738LC for Gas Turbine Blades

2006 ◽  
Vol 321-323 ◽  
pp. 509-512 ◽  
Author(s):  
Jung Seob Hyun ◽  
Gee Wook Song ◽  
Young Shin Lee
Keyword(s):  
Gas Turbine ◽  
Turbine Blades ◽  
Material Behavior ◽  
Experimental Program ◽  
Nickel Base Superalloy ◽  
Strain History ◽  
Stress Strain ◽  
Mechanical Fatigue ◽  
Nickel Base ◽  
Base Superalloy

A more accurate life prediction for gas turbine blade takes into account the material behavior under the complex thermo-mechanical fatigue (TMF) cycles normally encountered in turbine operation. An experimental program has been carried out to address the thermo-mechanical fatigue life of the IN738LC nickel-base superalloy. High temperature out-of-phase and in-phase TMF experiments in strain control were performed on superalloy materials. Temperature interval of 450-850 was applied to thermo-mechanical fatigue tests. The stress-strain response and the life cycle of the material were measured during the test. The mechanisms of TMF damage is discussed based on the microstructural evolution during TMF. The plastic strain energy based life pediction models were applied to the stress-strain history effect on the thermo-mechanical fatigue lives.

Brazing Process to Repair Wide Gap Cracks of Inconel 738 Superalloy Components

2009 ◽  
Vol 1242 ◽  
Author(s):  
Isidro Guzmán ◽  
Alejandro Garza ◽  
Felipe García ◽  
Jesús Castillo
Keyword(s):  
Cost Effective ◽  
Isothermal Solidification ◽  
Nickel Base Superalloy ◽  
Cost Effective Technique ◽  
Brazed Joints ◽  
Brazed Joint ◽  
Wide Gap ◽  
Nickel Base ◽  
Eds Microanalysis ◽  
Base Superalloy

ABSTRACTBrazing process is a cost effective technique to repair wide gap cracks in turbine components made from difficult to weld nickel base superalloys. In this process boron and silicon are used as melting point depressants, however, form hard and brittle intermetallic compounds with nickel (eutectic phases) which are detrimental to the mechanical properties of brazed joints. In this paper the effect of brazing parameters such as temperature and time on final microstructure of brazed joint of nickel base superalloy Inconel 738 using a commercial filler metal alloy (Ni-11Cr-3.5Si-2.25B-3.5Fe) was investigated. The microstructure of the joint layer was characterized by optical and scanning electron microscopy; chemical composition was carried out by energy dispersive X-ray spectrometry (EDS) microanalysis and microhardness testing. The results showed that the formation of eutectic microconstituents, within the joint regions, was significantly influenced by the brazing parameters and gap size, also that formation of eutectic constituents decreased by allowing a sufficient amount of time for a complete isothermal solidification to take place at the brazing temperature.

scholarly journals Development of Oxide Dispersion Strengthened Nickel-base Superalloy

1989 ◽  
Vol 75 (3) ◽  
pp. 529-536 ◽  
Author(s):  
Yozo KAWASAKI ◽  
Katsuyuki KUSUNOKI ◽  
Sizuo NAKAZAWA ◽  
Michio YAMAZAKI
Keyword(s):  
Oxide Dispersion Strengthened ◽  
Nickel Base Superalloy ◽  
Oxide Dispersion ◽  
Nickel Base ◽  
Base Superalloy

High-Temperature Low-Cycle Fatigue Behavior of 625 Nickel-Base Superalloy Welding Joint

2014 ◽  
Vol 618 ◽  
pp. 120-124
Author(s):  
Yuan Yuan Wang ◽  
Bao Sen Wang ◽  
Li Jia Chen
Keyword(s):  
High Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Properties ◽  
Nickel Base Superalloy ◽  
Cycle Fatigue ◽  
Welding Joint ◽  
Nickel Base ◽  
Base Superalloy

High temperature low cycle fatigue properties and fracture behavior of Inconel 625 nickel-base superalloy welding joint at 760oC were investigated under fully reversed total strain-controlled mode. The fatigue life and cyclic stress-strain data were analyzed to determine the individual strain fatigue parameters. It is noted that the welding joint exhibits the cyclic strain hardening and stability. The fatigue cracks initiate predominantly on the free surface of fatigue specimens and propagate in an intergranular mode or a mixed transgranular and intergranular mode.

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