Effect of Directional Solidification Condition on Interfacial Reaction between DD6 Single Crystal Superalloy and Zirconia-Silica Ceramic Core

2014 ◽  
Vol 926-930 ◽  
pp. 72-76
Author(s):  
Li Li Wang ◽  
Jia Rong Li ◽  
Ding Zhong Tang ◽  
Guo Hong Gu ◽  
Xin Li ◽  
...  
Keyword(s):  
Single Crystal ◽  
Directional Solidification ◽  
Interfacial Reaction ◽  
Optical Microscope ◽  
Single Crystal Superalloy ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Solidification Condition ◽  
Al Content ◽  
Interdependent System

The characterization of the interfaces between DD6 single crystal superalloy and zirconia-silica (ZrO2-SiO2) ceramic cores was performed by optical microscope (OM), SEM and EDS analysis in order to study the influence of directional solidification condition on the interfacial reaction. The results showed that there were chemical reactions on interfaces between DD6 melt and ZrO2-SiO2ceramic cores and the main reaction product was Al2O3. The interfacial reaction involved a complex, interdependent system including the oxidation of Al element, the destabilization of calcia stabilization zirconia (CSZ) and the formation of liquid phase with low melting point. The intensity of interfacial reaction increased with the increase of pouring temperature and solidification time, but the number and size of reaction zones could not increase together because of the limited Al content in DD6 alloy.

Formation Mechanism of Low Angle Boundary of DD6 Single Crystal Superalloy Blades

2012 ◽  
Vol 535-537 ◽  
pp. 1019-1022
Author(s):  
Z.X. Shi ◽  
J.R. Li ◽  
Shi Zhong Liu ◽  
J.Q. Zhao
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Single Crystal ◽  
Formation Mechanism ◽  
Selection Process ◽  
Optical Microscope ◽  
Single Crystal Superalloy ◽  
Competitive Growth ◽  
Solidification Condition ◽  
Scanning Electron

The specimens were machined from DD6 single crystal superalloy blades with low angle boundary. The misorientation of LAB was measured with EBSD technique in scanning electron microscope. The microstructures of specimens with LAB were examined in optical microscope and scanning electron microscope. The formation mechanism of low angle boundary of DD6 single crystal superalloy blades was investigated. The results showed that he formation of LAB which is caused by the deviating orientation from ideal [001] and the angle between the crystal orientation and shell is crystal selection process acted by dendrite competitive growth rule. Part of dendrites have changed their growth orientation a little to the decreasing [001] orientation departure angle because of solidification condition fluctuating during dendrites branching process. The LAB is the obvious interface between the deforming dendrites and their surrounding dendrites.

Oxidation behavior of Al/Y co-modified nanocrystalline coatings with different Al content on a nickel-based single-crystal superalloy

2020 ◽  
Vol 170 ◽  
pp. 108700 ◽  
Author(s):  
Shasha Yang ◽  
Yingqin Wang ◽  
Minghui Chen ◽  
Lanlan Yang ◽  
Jinlong Wang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Oxidation Behavior ◽  
Single Crystal Superalloy ◽  
Al Content

Modeling of grain selection during directional solidification of single crystal superalloy turbine blade castings

JOM ◽  
2010 ◽  
Vol 62 (5) ◽  
pp. 30-34 ◽  
Author(s):  
Dong Pan ◽  
Qingyan Xu ◽  
Baicheng Liu ◽  
Jiarong Li ◽  
Hailong Yuan ◽  
...  
Keyword(s):  
Single Crystal ◽  
Directional Solidification ◽  
Turbine Blade ◽  
Single Crystal Superalloy ◽  
Superalloy Turbine Blade

Fiber Coating Performance in TiAl

1994 ◽  
Vol 350 ◽  
Author(s):  
C. McCullough ◽  
R. R. Kieschke
Keyword(s):  
Mechanical Properties ◽  
Interfacial Reaction ◽  
Transport Problem ◽  
Transport Rate ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Chemical Behavior ◽  
Coating Performance ◽  
Fiber Coating ◽  
Alternative System

AbstractThe interfacial chemical behavior of two candidate coating systems for use on fine diameter (∼10 μm) Al2O3 in TiAl is presented. The performance of the Nb/Y2O3 system appears to be related to the transport rate of Ti through the Y2O3 layer. Interfacial reaction is then observed at points where the Y2O3 thickness is less than about 1 μm. The main reaction product formed appears to be an oxygen saturated TiAl phase. An alternative system, C/TiN/Y2O3 is then presented as a solution to the Ti transport problem and may offer more desirable interfacial mechanical properties.

Solid-state reaction of Pt thin film with single-crystal (001) β–SiC

1994 ◽  
Vol 9 (3) ◽  
pp. 648-657 ◽  
Author(s):  
J.S. Chen ◽  
E. Kolawa ◽  
M-A. Nicolet ◽  
R.P. Ruiz ◽  
L. Baud ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Single Crystal ◽  
Atomic Scale ◽  
Solid State Reactions ◽  
Main Reaction ◽  
Main Reaction Product ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Interlayer

Thermally induced solid-state reactions between a 70 nm Pt film and a single-crystal (001) β-SiC substrate at temperatures from 300 °C to 1000 °C for various time durations are investigated by 2 MeV He backscattering spectrometry, x-ray diffraction, secondary ion mass spectrometry, scanning electron microscopy, and cross-sectional transmission electron microscopy. Backscattering spectrometry shows that Pt reacts with SiC at 500 °C. The product phase identified by x-ray diffraction is Pt3Si. At 600–900 °C, the main reaction product is Pt2Si, but the depth distribution of the Pt atoms changes with annealing temperature. When the sample is annealed at 1000 °C, the surface morphology deteriorates with the formation of some dendrite-like hillocks; both Pt2Si and PtSi are detected by x-ray diffraction. Samples annealed at 500–900 °C have a double-layer structure with a silicide surface layer and a carbon-silicide mixed layer below in contact with the substrate. The SiC—Pt interaction is resolved at an atomic scale with high-resolution electron microscopy. It is found that the grains of the sputtered Pt film first align themselves preferentially along an orientation of {111}Pt//{001}SiC without reaction between Pt and SiC. A thin amorphous interlayer then forms at 400 °C. At 450 °C, a new crystalline phase nucleates discretely at the Pt-interlayer interface and projects into or across the amorphous interlayer toward the SiC, while the undisturbed amorphous interlayer between the newly formed crystallites maintains its thickness. These nuclei grow extensively down into the substrate region at 500 °C, and the rest of the Pt film is converted to Pt3Si. Comparison between the thermal reaction of SiC-Pt and that of Si–Pt is discussed.

Grain Competition Mechanism of a Ni3Al-Based Single Crystal Superalloy IC6SX

2013 ◽  
Vol 747-748 ◽  
pp. 797-803 ◽  
Author(s):  
Li Wu Jiang ◽  
Shu Suo Li ◽  
Mei Ling Wu ◽  
Ya Fang Han
Keyword(s):  
Single Crystal ◽  
Directional Solidification ◽  
Processing Parameters ◽  
Growth Direction ◽  
Selection Method ◽  
Single Crystal Superalloy ◽  
Competitive Growth ◽  
Deviation Angle ◽  
Spiral Grain ◽  
Competition Mechanism

The grain competitive growth and elimination during the directional solidification of a Ni3Al-base single crystal superalloy IC6SX prepared by spiral grain selection method was studied systematically. The experimental results revealed that there were 5 kinds of mechanism during the grain competitive growth and elimination. The grains with preferred growth direction and smaller deviation angle to growth direction have stronger competitiveness, and the mutual thwarting of dendrites played an important role in the processing of grains competitive growth. The results can explain the competitive growth mechanism during the directional solidification and can be used to optimize processing parameters to lay an important foundation for improving preparation processes of single crystal superalloys.

Directional Solidification Behavior of CMSX-6 Superalloy

2014 ◽  
Vol 788 ◽  
pp. 554-559
Author(s):  
Shuai Zheng ◽  
Yu Liang Jia ◽  
Jiao Tang
Keyword(s):  
Single Crystal ◽  
Directional Solidification ◽  
Thermal Gradient ◽  
First Generation ◽  
Primary Dendrite ◽  
Solidification Rate ◽  
Experimental Results ◽  
Single Crystal Superalloy ◽  
Solidification Behavior ◽  
Rate Range

The directional solidification behavior of a first generation single crystal superalloy CMSX-6 was investigated. The solidification rate range in 25μm/s to 100μm/s and a thermal gradient G of 30K/cm were used for the present study. The experimental results show that the primary dendrite arm space (PDAS) decreased from (432±8) μm to (369±4) μm as the solidification rate increased, and the sizes of the eutectic pools also decreased as the solidification rate increased. And the volume fractions of eutectic γ/γ' were about 7% to 9% with different solidification rate. The γ/γ'- eutectic was comprised with coarse γ' phase and fine γ/γ' network. The morphology of the γ/γ’ eutectic supported the possibility that the solidification of γ/γ’ eutectic initiates with the formation of fine γ/γ’.

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