Factors affecting the lamellar spacing in two-phase TiAl alloys with fully lamellar microstructures

2001 ◽  
Vol 36 (9) ◽  
pp. 1737-1742 ◽  
Author(s):  
Jiancheng Tang ◽  
Baiyun Huang ◽  
Kechao Zhou ◽  
Wensheng Liu ◽  
Yuehui He ◽  
...  
Keyword(s):  
Lamellar Spacing ◽  
Two Phase ◽  
Tial Alloys ◽  
Factors Affecting ◽  
Fully Lamellar

Hall–Petch relationship in two-phase TiAl alloys with fully lamellar microstructures

2002 ◽  
Vol 37 (7) ◽  
pp. 1315-1321 ◽  
Author(s):  
Jiancheng Tang ◽  
Baiyun Huang ◽  
Yuehui He ◽  
Wensheng Liu ◽  
Kechao Zhou ◽  
...  
Keyword(s):  
Two Phase ◽  
Tial Alloys ◽  
Petch Relationship ◽  
Fully Lamellar

Ultrafine Fully-Lamellar Structures in Two-Phase γ-TiAl Alloys

1996 ◽  
Vol 460 ◽  
Author(s):  
P. J. Maziasz ◽  
C. T. Liu
Keyword(s):  
Room Temperature ◽  
Interlamellar Spacing ◽  
Hot Extrusion ◽  
Processing Parameters ◽  
High Temperature Strength ◽  
Two Phase ◽  
Tial Alloys ◽  
Room Temperature Ductility ◽  
Heat Treated ◽  
Fully Lamellar

ABSTRACTSpecial ultrafine fully-lamellar microstructures have been found recently in γ-TiAl alloys with 46–48 at.% Al, when they are processed or heat-treated above the α-transus temperature (Tα). Hot-extrusion above Tα also produces a refined colony or grain size. Refined-colony/ultrafine-lamellar (RC/UL) microstructures produce an excellent combination of room-temperature ductility and high-temperature strength in Ti-47Al-2Cr-2Nb (at.%) alloys. UL structures generally have an average interlamellar spacing of 100–200 nm, and have regularly alternating γ and α2 lamellea, such that they are dominated by γ/α2 interfaces with relatively few γ/γ twin boundaries. The focus of this study is how variations in processing parameters or alloy composition affect formation of the UL structure, particularly the α2 component.

Numerical Simulations of Tensile Deformation Behavior in Two Phase α2 + γ Lamellar Tial Alloys

1994 ◽  
Vol 364 ◽  
Author(s):  
Bimal K. Kad ◽  
Ming Dao ◽  
Robert J. Asaro
Keyword(s):  
Volume Fraction ◽  
Tensile Deformation ◽  
Hydrostatic Stress ◽  
Fracture Initiation ◽  
Two Phase ◽  
Tial Alloys ◽  
Tensile Deformation Behavior ◽  
Mechanical Methods ◽  
Fully Lamellar ◽  
Stress Buildup

AbstractDeformation microstructures in γ-TiAl + α2Ti3Al based fully lamellar (FL) and nearly lamellar (NL) microstructures have been simulated using micro-mechanical methods. The deformation is extremely inhomogenous resulting in a large accumulation of hydrostatic stresses at the grain boundaries, thereby promoting intergranular fracture initiation. In particular, the increase in ductility with increasing equiaxed γ-grain volume fraction (with compliant deformation characteristics) in nearly lamellar alloys is explained by the reduction of the hydrostatic stress buildup at the boundaries, consequently mitigating fracture.

Implementation of Machine Learning Algorithms for Prediction of Fluidelastic Instability in Tube Arrays

2021 ◽  
Vol 143 (2) ◽  
Author(s):  
Joaquin E. Moran ◽  
Yasser Selima
Keyword(s):  
Machine Learning ◽  
Logistic Regression ◽  
Learning Algorithm ◽  
Machine Learning Algorithms ◽  
Two Phase ◽  
Factors Affecting ◽  
Logistic Regression Models ◽  
Number Of Factors ◽  
Tube Arrays ◽  
Fluidelastic Instability

Abstract Fluidelastic instability (FEI) in tube arrays has been studied extensively experimentally and theoretically for the last 50 years, due to its potential to cause significant damage in short periods. Incidents similar to those observed at San Onofre Nuclear Generating Station indicate that the problem is not yet fully understood, probably due to the large number of factors affecting the phenomenon. In this study, a new approach for the analysis and interpretation of FEI data using machine learning (ML) algorithms is explored. FEI data for both single and two-phase flows have been collected from the literature and utilized for training a machine learning algorithm in order to either provide estimates of the reduced velocity (single and two-phase) or indicate if the bundle is stable or unstable under certain conditions (two-phase). The analysis included the use of logistic regression as a classification algorithm for two-phase flow problems to determine if specific conditions produce a stable or unstable response. The results of this study provide some insight into the capability and potential of logistic regression models to analyze FEI if appropriate quantities of experimental data are available.

scholarly journals Creep of a fine-grained, fully-lamellar, two-phase TiAl alloy at 760{degree}C

10.2172/46701 ◽  
1995 ◽  
Author(s):  
J.N. Wang ◽  
A.J. Schwartz ◽  
T.G. Nieh ◽  
C.T. Liu ◽  
V.K. Sikka ◽  
...  
Keyword(s):  
Tial Alloy ◽  
Two Phase ◽  
Fine Grained ◽  
Fully Lamellar

scholarly journals Numerical Research on Performance of High-Speed Partial Emission Pump

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Qingjiao Shui ◽  
Ting Jiang ◽  
Binghui Pan ◽  
Tianxing Yang ◽  
Wei Pan
Keyword(s):  
Liquid Phase ◽  
High Speed ◽  
Phase Particle ◽  
Characteristic Curve ◽  
Particle Diameter ◽  
Two Phase ◽  
Factors Affecting ◽  
External Characteristic ◽  
Numerical Simulation Methods ◽  
Small Flow

The high-speed partial emission pump is a small flow and high-head pump, which has been widely used. To study the main factors affecting the performance of high-speed partial emission pumps, numerical simulation methods were used to calculate the performance parameters of high-speed partial emission pumps with and without inducers, and the external characteristic parameters were verified through comparison test values. The results show that the head of the high-speed partial emission pump with inducer is nearly 15 m higher than that of the high-speed partial emission pump without inducer. Considering the influence of air in the high-speed partial emission pump on the working performance, the two-phase flow with different flow rates, different particle sizes, and different concentrations was calculated, and the different liquid phase distributions, liquid phase velocity vector diagrams, and external characteristic curve were compared. The results show that under the same flow condition, the gas-phase particle diameter has the most severe influence on the external characteristic.

Ductile TiAl alloy with a Widmanstätten lamellar structure formed by rapid heating

2008 ◽  
Vol 23 (4) ◽  
pp. 949-953 ◽  
Author(s):  
J.P. Cui ◽  
M.L. Sui ◽  
Y.Y. Cui ◽  
D.X. Li
Keyword(s):  
Electric Current ◽  
Lamellar Structure ◽  
Tial Alloy ◽  
Rapid Heating ◽  
Pulse Treatment ◽  
Electric Current Pulse ◽  
Microstructural Refinement ◽  
Tial Alloys ◽  
Refinement Mechanism ◽  
Fully Lamellar

Instead of conventional grain-refinement treatments for improving the ductility of fully lamellar TiAl alloys, multiorientational, lamellar, subcolony refinement with good ductility has been achieved simply by using an electric-current pulse treatment. The microstructural refinement mechanism is attributed to the transformation on heating of γ laths in the prior large-grain lamellar structure to Widmanstätten α in several orientations, which on subsequent cooling forms lamellar structure colonies in multiple orientations. This kind of refined multiple-colony lamellar structure was found to enhance the ductility of the TiAl alloy.

scholarly journals A review of multiphase flow and deposition effects in film-cooled gas turbines

2018 ◽  
Vol 22 (5) ◽  
pp. 1905-1921 ◽  
Author(s):  
Jin Wang ◽  
Milan Vujanovic ◽  
Bengt Sunden
Keyword(s):  
Film Cooling ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Experimental Studies ◽  
Turbulence Models ◽  
Phase Flow ◽  
Two Phase ◽  
Film Cooling Effectiveness ◽  
Factors Affecting ◽  
Multi Phase Flow

This paper presents a review of particle deposition research in film-cooled gas turbines based on the recent open literature. Factors affecting deposition capture efficiency and film cooling effectiveness are analyzed. Experimental studies are summarized into two discussions in actual and virtual deposition environments. For investigation in virtual deposition environments, available and reasonable results are obtained by comparison of the Stokes numbers. Recent advances in particle deposition modeling for computational fluid dynamics are also reviewed. Various turbulence models for numerical simulations are investigated, and solutions for treatment of the particle sticking probability are described. In addition, analysis of injecting mist into the coolant flow is conducted to investigate gas-liquid two-phase flow in gas turbines. The conclusion remains that considerable re-search is yet necessary to fully understand the roles of both deposition and multi-phase flow in gas turbines.

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