Microstructural Changes during Thermal Fatigue in a Nickel-Base Directionally Solidified Superalloy

2013 ◽  
Vol 807-809 ◽  
pp. 2722-2725
Author(s):  
Kai Zhao
Keyword(s):  
Phase Transformation ◽  
Microstructural Evolution ◽  
Thermal Fatigue ◽  
Directionally Solidified ◽  
Microstructural Changes ◽  
The Matrix ◽  
Nickel Base

Microstructural evolution of a nickel-base directionally solidified superalloy during thermal fatigue was investigated. Three kinds of phase transformation have been observed: μ phase precipitated due to the relatively increasing of the concentration of forming μ phase elements as a result of the depletion of Al and Cr; Script-like carbides and γ phase dissolved into the matrix. Also, thermal fatigue was strongly influenced by oxidation.

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

Microstructural Evolution of Austenitic Stainless Steel AISI304 and AISI316 Subjected to High-Temperature Thermal Aging

2016 ◽  
Vol 857 ◽  
pp. 276-280 ◽  
Author(s):  
Hak Min Lee ◽  
Chung Seok Kim
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Microstructural Evolution ◽  
Thermal Aging ◽  
Austenitic Stainless Steels ◽  
Secondary Phases ◽  
Microstructural Changes ◽  
Long Period ◽  
Heat Treated

The purpose of this study is to investigate the microstructural evolution of austenitic stainless steels AISI304 and AISI316 subjected to thermal aging at elevated temperature. Most structural steels are generally subjected to softening of matrix when they are exposed to high temperatures for a long period of time because of the coarsening of the secondary phases and the phase transformation. The test specimens are heat-treated in electrical furnace for up to 5000 h at each predetermined aging time to simulate the degraded microstructure under high temperature. The microstructural changes in test materials have been evaluated by the optical and electron microscope in relation with twins, grains, precipitates, and phase transformation. The mechanical hardening were also discussed in terms of microstructural changes during long-term aging.

Influence of direction of notch on thermal fatigue property of a directionally solidified nickel base superalloy

Rare Metals ◽  
2011 ◽  
Vol 30 (S1) ◽  
pp. 472-476 ◽  
Author(s):  
Pengcheng Xia ◽  
Lei Yang ◽  
Jinjiang Yu ◽  
Xiaofeng Sun ◽  
Hengrong Guan ◽  
...  
Keyword(s):  
Thermal Fatigue ◽  
Fatigue Property ◽  
Nickel Base Superalloy ◽  
Directionally Solidified ◽  
Nickel Base ◽  
Base Superalloy

Effect of Notch Radius on the Thermal Fatigue Property of a New Guide Vane Materials

2014 ◽  
Vol 915-916 ◽  
pp. 572-575
Author(s):  
Peng Cheng Xia ◽  
Guan Peng Han ◽  
Kun Xie
Keyword(s):  
Thermal Fatigue ◽  
Guide Vane ◽  
Fatigue Property ◽  
Propagation Rate ◽  
Nickel Base Superalloy ◽  
Directionally Solidified ◽  
Notch Radius ◽  
Thermal Fatigue Crack ◽  
Initiation Increase ◽  
Nickel Base

Thermal fatigue property of a directionally solidified nickel-base superalloy with different notch radius was studied. The results show that cycle numbers of crack initiation increase and resistance of thermal fatigue decreases with the rise of notch radius at the upper temperature of 1050°C. Thermal fatigue crack initiates at carbide or oxidized cavity. The join of oxidized cavity makes crack propagate. The propagation rate lowers with the increasing notch radius. Crack propagation direction is along <110> direction in {111} plane. The stress concentration drops and thermal fatigue property improves with the increase of notched radius.

Thermal Fatigue Behavior of a Nickel-Base Directionally Solidified Superalloy

2013 ◽  
Vol 721 ◽  
pp. 312-315 ◽  
Author(s):  
Kai Zhao ◽  
Hai Jun Jiang ◽  
He Lin ◽  
Jun He Yang ◽  
Jian Chen
Keyword(s):  
Thermal Stress ◽  
Thermal Fatigue ◽  
Fatigue Behavior ◽  
Directionally Solidified ◽  
Thermal Fatigue Behavior ◽  
Nickel Base

Thermal fatigue behavior of a nickel-base directionally solidified superalloy was investigated using the notched flaky specimen. The da/dN K curve and da/dN-a relationship has been applied to analyze the thermal stress.

Effect of Recrystallization on Crack Initiation and Propagation during Creep in a Directionally Solidified Ni-Based Superalloy

2015 ◽  
Vol 816 ◽  
pp. 567-571
Author(s):  
Li Wang ◽  
Guang Xie ◽  
Jiu Han Xiao ◽  
Dong Ying Qiu ◽  
Yong Gao ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Creep Test ◽  
Gauge Length ◽  
Nickel Base Superalloy ◽  
Directionally Solidified ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation ◽  
The Matrix ◽  
Ebsd Technique ◽  
Nickel Base

Crack initiation and propagation during creep test in a recrystallization (RX) grain containing directionally solidified (DS) nickel-base superalloy was studied by employing electronic backscattered diffraction (EBSD) technique. Creep samples were locally deformed and then heat treated to get local RX at the center of the gauge length. Creep test was carried out at 980 °C/235 MPa. It was found that during creep test, precipitate free zones (PFZ) were formed along the RX grain boundary and the cracks were initiated and propagated along the interface (a) between PFZ and RX grains, (b) between PFZ and the matrix or (c) within PFZ. It indicated that the crack initiation and the propagation were crystal orientation dependent.

Coherency loss in γ' precipitates in nickel-base superalloy

1983 ◽  
Vol 41 ◽  
pp. 244-245
Author(s):  
R. A. Ricks ◽  
Angus J. Porter
Keyword(s):  
Lattice Mismatch ◽  
Lattice Parameter ◽  
Nickel Base Superalloy ◽  
Large Size ◽  
The Matrix ◽  
Nimonic 80A ◽  
Interfacial Dislocations ◽  
Nickel Base ◽  
Coherency Loss ◽  
Nimonic 115

During a recent investigation concerning the growth of γ' precipitates in nickel-base superalloys it was observed that the sign of the lattice mismatch between the coherent particles and the matrix (γ) was important in determining the ease with which matrix dislocations could be incorporated into the interface to relieve coherency strains. Thus alloys with a negative misfit (ie. the γ' lattice parameter was smaller than the matrix) could lose coherency easily and γ/γ' interfaces would exhibit regularly spaced networks of dislocations, as shown in figure 1 for the case of Nimonic 115 (misfit = -0.15%). In contrast, γ' particles in alloys with a positive misfit could grow to a large size and not show any such dislocation arrangements in the interface, thus indicating that coherency had not been lost. Figure 2 depicts a large γ' precipitate in Nimonic 80A (misfit = +0.32%) showing few interfacial dislocations.

MICROSTRUCTURAL EVOLUTION OF DIRECTIONALLY SOLIDIFIED Ni--BASED SUPERALLOY DZ125 UNDER PLANAR GROWTH

2010 ◽  
Vol 46 (9) ◽  
pp. 1075-1080 ◽  
Author(s):  
Zhixian MIN ◽  
Jun SHEN ◽  
Lingshui WANG ◽  
Zhourong FENG ◽  
Lin LIU ◽  
...  
Keyword(s):  
Microstructural Evolution ◽  
Directionally Solidified ◽  
Planar Growth
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