Effect of lamellar orientation on the strength and operating deformation mechanisms of fully lamellar TiAl alloys determined by micropillar compression

2017 ◽  
Vol 123 ◽  
pp. 102-114 ◽  
Author(s):  
Alberto Jesús Palomares-García ◽  
Maria Teresa Pérez-Prado ◽  
Jon Mikel Molina-Aldareguia
Keyword(s):  
Deformation Mechanisms ◽  
Tial Alloys ◽  
Lamellar Orientation ◽  
Micropillar Compression ◽  
Fully Lamellar

Microstructure and Creep of γ-TiAl Containing β-Stabilizer

2007 ◽  
Vol 539-543 ◽  
pp. 1543-1548 ◽  
Author(s):  
Dong Yi Seo ◽  
H. Saari ◽  
Peter Au ◽  
J. Beddoes
Keyword(s):  
Design Criterion ◽  
Grain Structure ◽  
Test Results ◽  
Directionally Solidified ◽  
Tial Alloys ◽  
Lamellar Orientation ◽  
Short And Long Term ◽  
Columnar Grain ◽  
Fully Lamellar

Fully lamellar structures of powder metallurgy (PM), investment cast, and directionally solidified (DS) TiAl alloys containing β stabilizer were produced after stepped cool heat treatment, and interface β precipitates were formed after aging at 950°C. In addition, a columnar grain structure combined with a fully lamellar structure aligned with the load direction and interface β precipitates were formed by directional solidification and subsequent heat treatments. Creep test results of PM TiAl indicate that controlling the initial microstructures is also critical for balancing the primary and steady-state creep resistance during short and long-term tests. DS TiAl alloy exhibits a significant reduction of the primary strain and creep rate compared to polycrystalline TiAl due to the unique DS microstructure. Therefore, a DS microstructure with proper lamellar orientation and controlled interface β precipitation is the ideal if maximum time to a relatively small (<0.5%) strain is the design criterion of merit.

Deformation mechanisms of basal slip, twinning and non-basal slips in Mg-Y alloy by micropillar compression

2021 ◽  
pp. 141408
Author(s):  
Na Li ◽  
Lingwei Yang ◽  
Chuanyun Wang ◽  
M.A. Monclús ◽  
Dongfeng Shi ◽  
...  
Keyword(s):  
Basal Slip ◽  
Deformation Mechanisms ◽  
Micropillar Compression

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

scholarly journals Deformation mechanisms of Mg-Ca-Zn alloys studied by means of micropillar compression tests

2021 ◽  
pp. 117151
Author(s):  
Jingya Wang ◽  
Yiwen Chen ◽  
Zhe Chen ◽  
Javier Llorca ◽  
Xiaoqin Zeng
Keyword(s):  
Deformation Mechanisms ◽  
Compression Tests ◽  
Micropillar Compression ◽  
Zn Alloys

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.

Microstructure Transformation of a Refined High Nb Containing TiAl Alloy

2013 ◽  
Vol 747-748 ◽  
pp. 38-43 ◽  
Author(s):  
Li Hua Chai ◽  
Liang Yang ◽  
Jian Peng Zhang ◽  
Zhi Yong Zhang ◽  
Lai Qi Zhang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Tial Alloy ◽  
High Strength ◽  
Temperature Limit ◽  
Tial Alloys ◽  
Β Phase ◽  
Α Phase ◽  
Refined Microstructure ◽  
Fully Lamellar ◽  
Sem Microstructure

High Nb containing TiAl alloys have been investigated traditionally as potential high temperature structural materials because of their high strength, good oxidation and creep resistance. However, the poor ductility and fracture toughness at room temperature limit their application, which could be improved by controlling microstructure to get refine and homogeneous fully lamellar structure. In this study, a high Nb containing TiAl alloy alloying Mn, B and Y with refined microstructure was produced. The solidification path was analyzed by DSC and SEM microstructure of the alloy was observed, after heating at a certain temperature for 1-24hrs and then quenching in water. The dissolution of β phase was also investigated. The results showed that the β phase could decompose only by heating in single β or near α phase field.

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

Influence of Step Aging on Creep Behavior and Microstructural Evolution of Fine-Grained Fully Lamellar XD TiAl Alloys

2007 ◽  
Vol 539-543 ◽  
pp. 1525-1530
Author(s):  
Han Liang Zhu ◽  
Dong Yi Seo ◽  
Kouichi Maruyama ◽  
Peter Au
Keyword(s):  
Creep Rate ◽  
Microstructural Evolution ◽  
Creep Behavior ◽  
Creep Deformation ◽  
Lamellar Structure ◽  
Aging Condition ◽  
Tial Alloys ◽  
Fine Grained ◽  
Fully Lamellar ◽  
Multiple Step

Fine-grained fully lamellar (FGFL) structures of XD TiAl alloys (Ti-45 and 47Al-2Nb-2Mn+0.8vol.%TiB2) (at.%) were stabilized to varying degrees by different aging treatments. Specimens with and without aging were creep tested at 760°C and 207 MPa. It was found that during creep deformation, degradation of the lamellar structure involving coarsening within the colonies and spheroidization at colony boundaries occurred, forming fine globular structures at the colony boundaries and increasing the creep rate. Aging treatments stabilized the lamellar structure and retarded the coarsening and spheroidization processes during creep deformation. As a result, the aged specimens exhibited lower minimum creep rates and longer creep lives than the unaged specimens. A multiple step aging stabilized the lamellar structure to the greatest extent and suppressed other degradation processes during aging, resulting in the best creep resistance. These results demonstrate that the multiple step aging is the optimal aging condition for stabilizing FGFL XD TiAl alloys.

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