Effect of Lamellar Spacing on Creep Strength of Ti-42mol%Al Alloy with Fully Lamellar Structure

1999 ◽  
Vol 171-174 ◽  
pp. 717-724
Author(s):  
Ryoichi Yamamoto ◽  
K. Mizoguchi ◽  
Kouichi Maruyama
Keyword(s):  
Creep Strength ◽  
Lamellar Structure ◽  
Lamellar Spacing ◽  
Al Alloy ◽  
Fully Lamellar

The Study on TiAl Based Alloy Blade Casting Structure by Bottom Pouring Vacuum Casting

2012 ◽  
Vol 503-504 ◽  
pp. 400-403
Author(s):  
Xi Cong Ye ◽  
Wei Guang Zhao ◽  
Wen Jun Liu ◽  
Shuang Qing Tang ◽  
Zi Fan Fang
Keyword(s):  
Lamellar Structure ◽  
Lamellar Spacing ◽  
Alloy Structure ◽  
Vacuum Suction ◽  
Vacuum Casting ◽  
Grain Sizes ◽  
Bottom Position ◽  
Blade Casting ◽  
Bottom To Top ◽  
Fully Lamellar

In this paper, the bottom pouring vacuum suction casting is used, and the TiAl-based alloy blade with a certain flexivity, the brim thickness 1.5mm, and the blade Falcon with high 8mm, width 10mm, length 27mm was obtained. The structures of this blade are studied. The grain sizes are different from bottom to top, in bottom position, the blade leaves structure have the equiaxed, and the central part have the columnar crystals. The TiAl-based alloy structures have fully lamellar. Comparing with different position structures, the bottom position TiAl based alloy structure have the least lamellar space, is about 0.13μm; the average space of top lamellar structure is about 0.38μm; the central region of the lamellar spacing slightly larger than the bottom area.

THE INVESTIGATION ON LAMELLAR MICROSTRUCTURE TRANSFORMATION AND STABILITY IN TIAL BASED INTERMATELLICS

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2279-2284
Author(s):  
WEI ZHANG ◽  
YUE MA ◽  
SHENGKAI GONG
Keyword(s):  
Lamellar Structure ◽  
Lamellar Microstructure ◽  
Lamellar Spacing ◽  
Microstructure Transformation ◽  
Β Phase ◽  
Microstructure Stability ◽  
The Stability ◽  
Fully Lamellar

Microstructure stability in fully lamellar (FL) structure TiAl based intermatellics have been studied. The experiment results have shown that the smaller the lamellar spacing is, the more instable the lamellar structure is. The distinct lamellar spheroidization occurs at 1150°C holding for 24h. This phenomena may be caused by lamellar coarsening and decomposition. The linear residual β phase distributed in the Ti -47 A 1-2 Cr -2 Nb alloy may prevent lamellar spheroidization and improves the stability of lamellar structure significantly.

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

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.

Evolution of Antiphase Domains and γ Lamellae in Ti-39at%Al Single Crystals

2006 ◽  
Vol 980 ◽  
Author(s):  
Yuichiro Koizumi ◽  
Kazuki Iwamoto ◽  
Takayuki Tanaka ◽  
Yoritoshi Minamino ◽  
Nobuhiro Tsuji
Keyword(s):  
Single Crystals ◽  
Structure Formation ◽  
Lamellar Structure ◽  
Lamellar Spacing ◽  
Antiphase Domain ◽  
Single Phase State ◽  
Preferential Nucleation ◽  
Phase Temperature ◽  
Antiphase Domains ◽  
The Moment

AbstractWe studied antiphase domain (APD) growth and lamellar structure formation during isothermal annealing of Ti-39at%Al single crystals at α2+γ dual phase temperature after quenching from α single phase state, intending to obtain a APD/lamellae mixed microstructure and to examine whether such a microstructure provides a strength higher than that obtained only by refining lamellar structure. The effect of plastic deformation prior to the annealing was also examined expecting a acceleration of γ lamellae formation through a preferential nucleation of γ-plates at dislocations. The lower was the annealing temperature, the smaller both the APD size and the lamellar spacing at the moment of a homogeneous lamellar structure formation tended to be, although naturally both the APD growth and the γ lamellae formation were slower. However, the APD size in the homogeneous lamellar structure was no smaller than 400 nm. A structure with finer APDs and finer lamellar structure was obtained by deforming the crystal before annealing since the lamellar structure formation was accelerated and the time for APD growth before the lamellar structure formation was shortened. For instance, a structure with an average lamellar spacing of 88 nm and an average APD size of 214 nm was obtained by deforming the crystals to 10 % plastic strain and subsequently annealing at 1073 K for 1×104 s, while no γ plate was obtained only by such an annealing without deformation.

Hot deformation behavior and processing maps of Ti–6Al–4V alloy with starting fully lamellar structure

2018 ◽  
Vol 33 (22) ◽  
pp. 3677-3688 ◽  
Author(s):  
Wenjing Zhang ◽  
Hua Ding ◽  
Jingwei Zhao ◽  
Bo Yang ◽  
Wenjing Yang
Keyword(s):  
Hot Deformation ◽  
Deformation Behavior ◽  
Lamellar Structure ◽  
Processing Maps ◽  
Hot Deformation Behavior ◽  
Image Position ◽  
Fully Lamellar

Abstract

C11b/C40 Lamellar Structure in a Ta-added Molybdenum Disilicide

2000 ◽  
Vol 646 ◽  
Author(s):  
Fu-Gao Wei ◽  
Yoshisato Kimura ◽  
Yoshinao Mishima
Keyword(s):  
Mechanical Properties ◽  
Orientation Relationship ◽  
Binary Alloy ◽  
Lamellar Structure ◽  
Molybdenum Disilicide ◽  
Lamellar Microstructure ◽  
Polycrystalline Alloys ◽  
Lamellar Interface ◽  
Fully Lamellar ◽  
Microstructural Control

ABSTRACTC11b/C40 fully lamellar microstructures, similar to the well-known TiAl/Ti3Al lamellae, were obtained in Ta- and Nb-added MoSi2 polycrystalline alloys in a previous work. In the present study, the crystallography of the lamellar structure is investigated in a MoSi2-15mol%TaSi2 pseudo-binary alloy after homogenized at 1400°C for 168h, in order to provide some useful parameters for microstructural control to improve mechanical properties. The orientation relationship between C11b and C40 phases and its three distinct variants were identified. Coherency of the lamellar interface is analyzed in comparison with the TiAl/Ti3Al lamellae. Approach to modify the C11b/C40 lamellar microstructure to increase its coherency is discussed based on the results obtained.

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