Phase transformation and microstructural control of the α-solidifying γ-Ti-45Al-2Nb-0.7Cr-0.3Si intermetallic alloy

M. N. Mathabathe; S. Govender; A. S. Bolokang; R. J. Mostert; C. W. Siyasiya

doi:10.1016/j.jallcom.2018.05.051

Phase transformation and microstructural control of the α-solidifying γ-Ti-45Al-2Nb-0.7Cr-0.3Si intermetallic alloy

M. N. Mathabathe, S. Govender, A. S. Bolokang, R. J. Mostert, C. W. Siyasiya

Research output: Contribution to journal › Article › peer-review

31 Citations (Scopus)

Abstract

The γ-Ti-45Al-2Nb-0.7Cr-0.3Si based intermetallic alloy was developed. Microstructure evolution of the as-cast and heat-treated alloy yielded the spheriodised and Widmanstätten laths. High temperature differential thermal analysis (HTDTA) was performed on the as-cast Ti-45Al-2Nb-0.7Cr-0.3Si alloy in order to determine critical temperatures and provide insight into phase transformations prior heat treatment. The morphology of the alloy was analysed by the optical microscopy, scanning and transmission electron microscopy (SEM/TEM). The SEM was equipped with energy dispersion spectroscopy (EDS) for chemical composition. The EBSD mapping was employed to determine microstructural evolution. The results show that after heat-treatment the homogeneous microstructures were obtained, compared to the dendritic as-cast structure. The spheriodised laths were seen embedded inside the lamellar structure; whereas the Widmanstätten laths were observed as crossed/needle like (α₂+γ) laths of small spacing, with a spatial orientation with respect to the lamellar structure. The structural development was determined by the X-ray diffraction (XRD).

Original language	English
Pages (from-to)	8-15
Number of pages	8
Journal	Journal of Alloys and Compounds
Volume	757
DOIs	https://doi.org/10.1016/j.jallcom.2018.05.051
Publication status	Published - 15 Aug 2018
Externally published	Yes

Keywords

DTA
Heat-treatment
Phase transformation
Solidification
γ-TiAl based alloy

ASJC Scopus subject areas

Mechanics of Materials
Mechanical Engineering
Metals and Alloys
Materials Chemistry

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10.1016/j.jallcom.2018.05.051

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title = "Phase transformation and microstructural control of the α-solidifying γ-Ti-45Al-2Nb-0.7Cr-0.3Si intermetallic alloy",

abstract = "The γ-Ti-45Al-2Nb-0.7Cr-0.3Si based intermetallic alloy was developed. Microstructure evolution of the as-cast and heat-treated alloy yielded the spheriodised and Widmanst{\"a}tten laths. High temperature differential thermal analysis (HTDTA) was performed on the as-cast Ti-45Al-2Nb-0.7Cr-0.3Si alloy in order to determine critical temperatures and provide insight into phase transformations prior heat treatment. The morphology of the alloy was analysed by the optical microscopy, scanning and transmission electron microscopy (SEM/TEM). The SEM was equipped with energy dispersion spectroscopy (EDS) for chemical composition. The EBSD mapping was employed to determine microstructural evolution. The results show that after heat-treatment the homogeneous microstructures were obtained, compared to the dendritic as-cast structure. The spheriodised laths were seen embedded inside the lamellar structure; whereas the Widmanst{\"a}tten laths were observed as crossed/needle like (α2+γ) laths of small spacing, with a spatial orientation with respect to the lamellar structure. The structural development was determined by the X-ray diffraction (XRD).",

keywords = "DTA, Heat-treatment, Phase transformation, Solidification, γ-TiAl based alloy",

author = "Mathabathe, {M. N.} and S. Govender and Bolokang, {A. S.} and Mostert, {R. J.} and Siyasiya, {C. W.}",

note = "Publisher Copyright: {\textcopyright} 2018 Elsevier B.V.",

year = "2018",

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day = "15",

doi = "10.1016/j.jallcom.2018.05.051",

language = "English",

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T1 - Phase transformation and microstructural control of the α-solidifying γ-Ti-45Al-2Nb-0.7Cr-0.3Si intermetallic alloy

AU - Mathabathe, M. N.

AU - Govender, S.

AU - Bolokang, A. S.

AU - Mostert, R. J.

AU - Siyasiya, C. W.

PY - 2018/8/15

Y1 - 2018/8/15

N2 - The γ-Ti-45Al-2Nb-0.7Cr-0.3Si based intermetallic alloy was developed. Microstructure evolution of the as-cast and heat-treated alloy yielded the spheriodised and Widmanstätten laths. High temperature differential thermal analysis (HTDTA) was performed on the as-cast Ti-45Al-2Nb-0.7Cr-0.3Si alloy in order to determine critical temperatures and provide insight into phase transformations prior heat treatment. The morphology of the alloy was analysed by the optical microscopy, scanning and transmission electron microscopy (SEM/TEM). The SEM was equipped with energy dispersion spectroscopy (EDS) for chemical composition. The EBSD mapping was employed to determine microstructural evolution. The results show that after heat-treatment the homogeneous microstructures were obtained, compared to the dendritic as-cast structure. The spheriodised laths were seen embedded inside the lamellar structure; whereas the Widmanstätten laths were observed as crossed/needle like (α2+γ) laths of small spacing, with a spatial orientation with respect to the lamellar structure. The structural development was determined by the X-ray diffraction (XRD).

AB - The γ-Ti-45Al-2Nb-0.7Cr-0.3Si based intermetallic alloy was developed. Microstructure evolution of the as-cast and heat-treated alloy yielded the spheriodised and Widmanstätten laths. High temperature differential thermal analysis (HTDTA) was performed on the as-cast Ti-45Al-2Nb-0.7Cr-0.3Si alloy in order to determine critical temperatures and provide insight into phase transformations prior heat treatment. The morphology of the alloy was analysed by the optical microscopy, scanning and transmission electron microscopy (SEM/TEM). The SEM was equipped with energy dispersion spectroscopy (EDS) for chemical composition. The EBSD mapping was employed to determine microstructural evolution. The results show that after heat-treatment the homogeneous microstructures were obtained, compared to the dendritic as-cast structure. The spheriodised laths were seen embedded inside the lamellar structure; whereas the Widmanstätten laths were observed as crossed/needle like (α2+γ) laths of small spacing, with a spatial orientation with respect to the lamellar structure. The structural development was determined by the X-ray diffraction (XRD).

KW - DTA

KW - Heat-treatment

KW - Phase transformation

KW - Solidification

KW - γ-TiAl based alloy

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Phase transformation and microstructural control of the α-solidifying γ-Ti-45Al-2Nb-0.7Cr-0.3Si intermetallic alloy

Abstract

Keywords

ASJC Scopus subject areas

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