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.

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.

scholarly journals Bionic Repair of Thermal Fatigue Cracks in Ductile Iron by Laser Melting with Different Laser Parameters

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 101 ◽  
Author(s):  
Siyuan Ma ◽  
Ti Zhou ◽  
Hong Zhou ◽  
Geng Chang ◽  
Benfeng Zhi ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Thermal Fatigue ◽  
Ductile Iron ◽  
Laser Energy ◽  
Fatigue Cracks ◽  
Fatigue Cracking ◽  
Unit Distance ◽  
Thermal Fatigue Resistance ◽  
Brake Discs ◽  
Thermal Fatigue Cracks

Nodular iron brake discs typically fail due to serious thermal fatigue cracking, and the presence of graphite complicates the repair of crack defects in ductile iron. This study presents a novel method for remanufacturing ductile iron brake discs based on coupled bionics to repair thermal fatigue cracks discontinuously using bio-inspired crack blocking units fabricated by laser remelting at various laser energy inputs. Then, the ultimate tensile force and thermal fatigue crack resistance of the obtained units were tested. The microhardness, microstructure, and phases of the units were characterized using a digital microhardness meter, optical microscopy, scanning electron microscopy, and X-ray diffraction. It was found that the units without defects positively impacted both the thermal fatigue resistance and tensile strength. The unit fabricated at a laser energy of 165.6 − 15 + 19 J/ mm 2 had sufficient depth to fully close the crack, and exhibited superior anti-cracking and tensile properties. When the unit distance is 3 mm, the sample has excellent thermal fatigue resistance. In addition, the anti-crack mechanism of the units was analysed.

Effect of Pre-Weld Heat Treatment Temperatures on TIG Welded Microstructures on Nickel Base Superalloy, GTD-111

2015 ◽  
Vol 658 ◽  
pp. 14-18
Author(s):  
Tanaporn Rojhirunsakool ◽  
Duangkwan Thongpian ◽  
Nutthita Chuankrerkkul ◽  
Panyawat Wangyao
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Tig Welding ◽  
Nickel Base Superalloy ◽  
Nickel Base ◽  
Base Superalloy ◽  
Weld Heat

Nickel-base superalloys have been used as high temperature materials in land-base gas turbine application. When subjected to long term, high temperature service, large crack propagation was observed. Typical refurbishment method of these turbines is carried out by using TIG welding followed by post-weld standard heat treatment. However, new crack initiation is found in the heat-affected zone after TIG welding. Pre-weld heat treatment has been discovered to improves final γ + γ’ microstructure. This study focuses on the effect of pre-weld heat treatment temperature on final γ + γ’ microstructure. Seven different conditions of pre-weld heat treatment temperature were investigated. Scanning electron microscopy studies were carried out after pre-weld and post-weld heat treatments to compare the γ + γ’ microstructure and capture microcracks. The best pre-weld heat treatment temperature produces uniform distribution of finely dispersed γ’ precipitates in the γ matrix without post-weld crack.

scholarly journals Effect of Heat Treatment Process on Microstructure and Fatigue Behavior of a Nickel-Base Superalloy

Materials ◽  
2015 ◽  
Vol 8 (9) ◽  
pp. 6179-6194 ◽  
Author(s):  
Peng Zhang ◽  
Qiang Zhu ◽  
Gang Chen ◽  
Heyong Qin ◽  
Chuanjie Wang
Keyword(s):  
Heat Treatment ◽  
Treatment Process ◽  
Fatigue Behavior ◽  
Nickel Base Superalloy ◽  
Heat Treatment Process ◽  
Nickel Base ◽  
Base Superalloy

A New Method to Study the Thermal Fatigue Resistance of Molybdenum by High Power Laser Irradiation

2012 ◽  
Vol 184-185 ◽  
pp. 1384-1388 ◽  
Author(s):  
Shuai Lu ◽  
Hong Wei Li ◽  
Dun Bo Yu ◽  
Ming Pang ◽  
Bo Wang
Keyword(s):  
Fatigue Resistance ◽  
Thermal Fatigue ◽  
High Power ◽  
Laser Heating ◽  
Fatigue Cracks ◽  
Crack Density ◽  
Scale Production ◽  
High Power Laser ◽  
Power Laser ◽  
Thermal Fatigue Resistance

In single roll rapid quenching molding, especially for the preparation of amorphous ribbons and rare earth permanent magnetic materials, the chilling roll is an extremely important component of the preparation equipment. However, frequent repair of the roll is not conducive to continuous large-scale production because of its poor thermal fatigue resistance. Molybdenum is gradually being used as chilling roll material in some applications, and in the present paper a new approach to study the thermal fatigue resistance of molybdenum is based on laser pulse irradiation on the molybdenum surface. A new designed device effectively prevents the molybdenum to be oxidized during the laser heating test. The experiments of thermal fatigue damage on molybdenum were conducted by the high power laser. The results shows that the fatigue cracks had been propagated in the irradiated region after the specimen was loaded by 200 times pulsed laser heating. There is a greater crack density in the laser heating brim region than in the center of the irradiated region. According to the transgranular mode of crack propagation in the laser heating brim region and intergranular mode in the center of the irradiated region, the maximum stress took place at the intersection region due to the great temperature gradient in the laser heating brim region. Continued basis-oriented experiments are planned, regarding the mechanism of thermal fatigue crack initiation and propagation for chilling roll materials.

Long-Term Gamma Prime Phase Stability after Various Heat Treatment Conditions with Temperature Dropping during Solution Treatment in Cast Nickel Base Superalloy, Grade Inconel-738

2017 ◽  
Vol 891 ◽  
pp. 420-425
Author(s):  
Sureerat Polsilapa ◽  
Aimamorn Promboopha ◽  
Panyawat Wangyao
Keyword(s):  
Heat Treatment ◽  
Turbine Blades ◽  
Solution Treatment ◽  
Nickel Base Superalloy ◽  
Gamma Prime ◽  
Nickel Based Superalloy ◽  
Treatment Conditions ◽  
Nickel Base ◽  
Base Superalloy

Cast nickel based superalloy, Grade Inconel 738, is a material for turbine blades. Its rejuvenation heat treatment usually consist of solution treatment condition with temperature range of 1125-1205 oC for 2-6 hours. Then it is following with double aging process including primary aging at 1055oC for 1 hour and secondary aging at 845oC for 24 hours. However, the various selected temperature dropping program were performed during solution treatment to simulate the possible error of heating furnace. The maximum number of temperature dropping during solution treatment is varied from 1-3 times From all obtained results, the various temperature dropping during solution treatment conditions showed extremely the significant effect on the final rejuvenated microstructures and long-term gamma prime stability after heating at temperature of 900oC for 200 hours.

Microstructural evolution of a directionally solidified nickel-base superalloy during thermal fatigue

Rare Metals ◽  
2011 ◽  
Vol 30 (S1) ◽  
pp. 477-481 ◽  
Author(s):  
Pengcheng Xia ◽  
Lei Yang ◽  
Jinjiang Yu ◽  
Xiaofeng Sun ◽  
Hengrong Guan ◽  
...  
Keyword(s):  
Microstructural Evolution ◽  
Thermal Fatigue ◽  
Nickel Base Superalloy ◽  
Directionally Solidified ◽  
Nickel Base ◽  
Base Superalloy
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