On the structure of the B2 phase in Ti–Al–Mo alloys

Singh, A. K.; Banumathy, S.; Sowjanya, D.; Rao, M.

doi:10.1063/1.2931004

Cited by 15 publications

(16 citation statements)

References 14 publications

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“…The B2 phase contains two distinct sublattices A and B, which are located at the cell corners (0, 0, 0) and at body-centered positions (1/2, 1/2, 1/2). The site occupancy of the B2 has been studied by several investigators using X-ray and neutron diffraction techniques [5,9,[11][12][13][14]. These results can be classified into two groups: (1) The alloys containing titanium 50 atom% and (2) the alloys containing Ti !50 atom%.…”

Section: Resultsmentioning

confidence: 99%

“…The excess Ti atoms are occupied on B sites. The alloys studied by Azad et al [9] and Singh et al [14] belong to this class. The site occupancy of the present experimental alloy should not follow this trend since Ti and Zr belong to group X and also the same type of element.…”

Section: Resultsmentioning

confidence: 99%

“…The elements in groups X and M exhibit a (close packed hexagonal (cph) structure) and b (body-centered cubic (bcc) structure) phases at room temperature, respectively. The stoichiometry of the B2 phase has been reported as either X 2 AlM or X 4 Al 3 M although it has been observed to have several non-stoichiometric compositions with wide range of X, Al and M concentrations [4][5][6][7][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

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Structure and stability of the B2 phase in Ti–25Al–25Zr alloy

2009

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Structure and stability of the B2 phase in Ti–25Al–25Zr alloy

2009

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“…The elements X and M exhibit cph (close packed hexagonal) and bcc (body centered cubic) structures, respectively. The stoichiometry of B2 phase has been reported to be X 2 AlM or X 4 Al 3 M although this has also been reported to have several non-stoichiometric compositions with wide range of X, Al and M concentrations [4,[7][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…This has been correlated with the microstructure and hardness before and after the compression test. The work hardening behavior of this alloy at room temperature has been compared with those of other B2 alloys reported in literature [14,18,19].…”

Section: Introductionmentioning

confidence: 99%

Deformation behavior of an ordered B2 phase in Ti–25Al–25Zr alloy

Manda

Singh

2010

Intermetallics

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In Situ Observation of Various Phase Transformation Paths in Nb‐Rich TiAl Alloys during Quenching with Different Rates

et al. 2011

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Intermetallic g-TiAl based alloys are a class of novel, light-weight structural materials with attractive mechanical properties for advanced high-temperature applications. Due to their low density (4 g cm À3 ), their high yield and creep strength up to 800 8C and their good oxidation resistance they have the potential to replace the heavier Ni-based superalloys (8 g cm À3 ) in industrial and in aviation gas turbines as well as in automobile engines. [1] Conventional titanium aluminide alloys consist of tetragonal g-TiAl (L1 0 structure; P 4/m m m) and small small amounts of hexagonal a 2 -Ti 3 Al (D0 19 structure; P 6 3 /m m c). Through special heat treatments various microstructures can be established in these two phase alloys to optimize their mechanical properties. [2] The most restricting factor for a broad industrial implementation of titanium aluminides is their low ductility that also limits their workability. A promising design strategy to overcome the brittleness and to improve the hot workability is to induce the formation of more ductile phases by adding ternary alloying elements. The body-centered cubic (bcc) high-temperature b-Ti(Al) phase (A2 structure; I m 3 m) can act as a ductilizing phase in TiAl alloys because it provides a high number of independent slip systems. In recent years several authors have reported that stabilizing the b phase by alloying elements such as Nb, Mo, Ta, or V, significantly improves the hot workability. [3][4][5] Additionally, novel types of microstructures can be achieved exploiting the ternary solid state transformations. [3,4] In spite of this progress, the exact pathway of phase transformations and thus the evolution of microstructures in b phase containing TiAl alloys are not fully understood up to now. At lower temperatures, the disordered bcc b phase can transform to ordered cubic b o -TiAl phase (B2 structure; P m 3 m). However, calculated and experimental transition temperatures show large discrepancies. [6,7] In high-Nb containing TiAl alloys b and/or b o can decompose to ordered hexagonal v o -Ti 4 Al 3 Nb phase (B8 2 structure; P 6 3 /m m c). [8,9] The formation of an orthorhombic phase (B19 structure; P m m a) is reported in Al-lean and Nb-rich TiAl alloys and is interpreted as a transition structure between the cubic b and/ or b o and the orthorhombic O-Ti 2 AlNb phase (C m c m). [4] The crystallographic data of all phases mentioned above and relevant for this work are listed in Table 1.Ordered phases, such as b o and v o , are often assumed to be detrimental to ductility due to their low crystal symmetry. Otherwise the orthorhombic O phase is known to be relatively ductile and even v o containing TiAl alloys show good plastic formability at 800 8C. [8] Thus, with respect to alloy design and processing, it is of high importance to know which kind of additional phase will be formed and which further phase transformations occur during processing and service.In recent years intermetallic g-TiAl based alloys with additional amounts of the ternary b phase have a...

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On the structure of the B2 phase in Ti–Al–Mo alloys

Cited by 15 publications

References 14 publications

Structure and stability of the B2 phase in Ti–25Al–25Zr alloy

Structure and stability of the B2 phase in Ti–25Al–25Zr alloy

Deformation behavior of an ordered B2 phase in Ti–25Al–25Zr alloy

In Situ Observation of Various Phase Transformation Paths in Nb‐Rich TiAl Alloys during Quenching with Different Rates

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