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Journal ArticleDOI

Effects of aluminum content and microstructure on tensile properties of TiAl alloys

01 Apr 1996-Scripta Materialia (Pergamon)-Vol. 34, Iss: 7, pp 1147-1154
TL;DR: In this paper, the effect of microstructure on the room temperature tensile properties of polycrystalline Ti-49 and 51A1 alloys were investigated in vacuum, where aging in the γ single-and γ + α two-phase fields, followed by air cooling or controlled cooling (5K/min), results in three types of microstructures: type (I), equiaxed γ grain structure, type (II), γgrain structure with α 2 γ laths formed mainly at the ǫ grain boundaries, and type (
About: This article is published in Scripta Materialia.The article was published on 1996-04-01. It has received 16 citations till now. The article focuses on the topics: Grain boundary & Grain size.
Citations
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Journal ArticleDOI
Shili Shu1, Feng Qiu1, Sijie Lü1, Shenbao Jin1, Qi-Chuan Jiang1 
TL;DR: In this paper, the phase transitions in the TiAl and the Ti-Al-C/TiAl systems are investigated by the differential thermal analysis (DTA) and X-ray diffraction (XRD).
Abstract: The phase transitions in the Ti–Al and the Ti–Al–C systems are investigated by the differential thermal analysis (DTA) and X-ray diffraction (XRD). The results reveal that the addition of C not only leads to the formation of the Ti 2 AlC phase but also lowers the formation temperatures of the TiAl and Ti 3 Al phases. In the both systems, the combustion synthesis reactions are ignited at the melting point of Al, so the TiAl alloy and the Ti 2 AlC/TiAl composites are successfully fabricated at a lower temperature (about 660 °C) with an applied pressure. The yield strength, the ultimate compression strength and the work hardening rate of the Ti 2 AlC/TiAl composites are all higher than those of the TiAl alloy and increase with the increase in the Ti 2 AlC content. The average ultimate compression strength of the 6 vol.% Ti 2 AlC/TiAl composite is 179 MPa higher than that of the TiAl alloy without sacrificing ductility.

41 citations

Journal ArticleDOI
TL;DR: In this article, the effect of MoO 3 content on the microstructure and mechanical properties of (Ti,Mo)Al/Al 2 O 3 composites was investigated in detail.

38 citations

Journal ArticleDOI
Shili Shu1, Feng Qiu1, Bin Xing1, Shenbao Jin1, Yawei Wang1, Qi-Chuan Jiang1 
TL;DR: In this article, the effect of Mn atoms on the mechanical properties of the Ti2AlC/TiAl composites was investigated by experiments and first principles calculations, and the results showed that the addition of Mn remarkably improves the ductility of the composites.

32 citations


Cites background from "Effects of aluminum content and mic..."

  • ...However, their insufficient strength, low ductility and poor fracture toughness restrict their practical applications [1,2,5]....

    [...]

Journal ArticleDOI
Shili Shu1, Feng Qiu1, Shenbao Jin1, Jianbang Lu1, Qi-Chuan Jiang1 
TL;DR: In this article, the effect of the (Nb-C) content on the compression properties and work-hardening behavior of the composites has been investigated and it was shown that the TiAl alloy improved remarkably with the addition of the Nb−C elements due to the formation of Ti 2 AlC particles and the solid solution of Nb in the Ti-Al matrix.

31 citations


Cites background or methods from "Effects of aluminum content and mic..."

  • ...However, the low ductility and fracture toughness at ambient temperature limit the practical use of the TiAl alloy [1,2,5]....

    [...]

  • ...During the past decades, a significant effort has focused on the development of the acceptable ambient temperature ductility and fracture toughness of the TiAl alloy, mainly through the methods of composition optimization and microstructure control [2,4–7]....

    [...]

Journal ArticleDOI
Hao Wu1, Xiping Cui1, Lin Geng1, G.H. Fan1, J.C. Pang1, L.S. Wei1 
TL;DR: In this paper, the phase transitions and reaction mechanisms at various annealing stages were investigated for microlaminated composite sheets consisting of alternating TiAl and carbide-layers.

21 citations

References
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Journal ArticleDOI
01 Jul 1994-JOM
TL;DR: In this paper, an improved understanding of both fundamental and practical aspects of these aluminides, such as phase relations, microstructure evolution and control, processing, micro-structure-property relationships, and deformation and fracture processes, is presented.
Abstract: Extensive research during the last eight years has resulted in the development and improvement of second-generation gamma alloys of engineering importance, Ti-48Al-2(Cr or Mn)-2Nb and derivatives. These alloys exhibit properties, in duplex micro-structural forms, meeting requirements for some gas-turbine and automobile engine components that may be used up to 760 °C. These achievements were made possible by an improved understanding of both fundamental and practical aspects of these aluminides, such as phase relations, microstructure evolution and control, processing, microstructure-property relationships, and deformation and fracture processes. Nevertheless, widespread higher performance and/or higher-temperature applications of these alloys appear unlikely unless the current properties are dramatically improved.

722 citations

Journal ArticleDOI
01 Aug 1991-JOM
TL;DR: In this article, the authors present a review of the current understanding of the above specific aspects and the processing-microstructure-property relationships, and identify pacing problems and applications, as well as identify pacing issues and applications.
Abstract: During the last two years remarkable improvements have been made in the properties (such as toughness and creep) and processing technology of gamma titanium aluminides, making them potentially viable engineering alloys for high-temperature structural applications. These achievements were made possible by a greater understanding of both the fundamental and the practical aspects of these aluminides, such as phase relationships, the effects of alloying elements, deformation mechanisms, microstructure evolution and processing. This article reviews the current understanding of the above specific aspects and the processing-microstructure-property relationships, and identifies pacing problems and applications.

571 citations

Journal ArticleDOI
TL;DR: A two-phase gamma titanium aluminide alloy, Ti-47Al-1Cr-1V-2.5Nb, was studied under forged and various subsequent heat treatment conditions, to investigate the microstructural evolution and the effect of microstructure on room temperature (RT) tensile properties and fracture toughness behavior as discussed by the authors.
Abstract: A two-phase gamma titanium aluminide alloy, Ti-47Al-1Cr-1V-2.5Nb (in at.%), was studied under forged and various subsequent heat treatment conditions, to investigate the microstructural evolution and the effect of microstructure on room temperature (RT) tensile properties and fracture toughness behavior. Four classes of microstructure and three types of lamellar formation were identified, and their formation mechanisms were analyzed using various analytical techniques including metallography, electron optics, differential thermal analysis (DTA), and crystallography. It was found that both tensile and toughness behavior were profoundly affected by the microstructural variations.

391 citations

Journal ArticleDOI
TL;DR: The tensile properties of the intermetallic compound Ti3Al have been determined in air at several temperatures within the range of 25 to 900 °C as discussed by the authors and the fracture modes were studied in the scanning electron microscope.
Abstract: The tensile properties of the intermetallic compound Ti3Al have been determined in air at several temperatures within the range of 25 to 900 °C. The dislocation structures produced by the various testing conditions were studied in the electron microscope and the fracture modes were studied in the scanning electron microscope. These microstructural observations were correlated with the mechanical properties. The results indicate that Ti3Al has only limited ductility even at 900 °C. The apparent ductile-brittle transition which occurs above 600 °C is due to increasing amounts of intergranular cracking. Some increase in ductility above 600 °C is due to the onset of dislocation cross slipping. The fracture mode up to 600 °C is entirely cleavage. Above 600 °C the fracture shows increasing evidence of plasticity; however, cleavage remains the main fracture mode up to 900 °C.

184 citations