Microstructural evolution of massively transformed {gamma}-TiAl during isothermal aging

Journal Article · Sat Mar 01 04:00:00 EST 1997 · Scripta Materialia

DOI:https://doi.org/10.1016/S1359-6462(96)00416-2· OSTI ID:455188

Kumagai, T; Abe, E; Nakamura, M ^[1]; Takeyama, M ^[2]

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1. National Research Inst. for Metals, Tsukuba, Ibaraki (Japan)
2. Tokyo Inst. of Tech. (Japan)

{gamma}-TiAl base alloys have been expected as high-temperature structural materials because of their superior properties such as high specific elastic modulus and strength, high melting temperature and reasonable oxidation resistance. Recently, the authors reported that the microstructure changes from a massively transformed {gamma} grain structure to a equiaxed {gamma} grain structure involving fine {alpha}{sub 2} particles both in the {gamma} grain interiors and at the {gamma} grain boundaries, when a Ti-48at.%Al alloy quenched from an {alpha} phase field was isothermally aged in an {alpha}{sub 2} + {gamma} two phase field. More recently, Wen et al. suggested that this reaction occurs through the following two stages: (1) precipitation of thin {alpha}{sub 2} plates and small {alpha}{sub 2} particles, and (2) spheroidization of the fine {alpha}{sub 2} plates and growth of the {alpha}{sub 2} particles. However, the detailed formation mechanism of the {alpha}{sub 2} particles, especially the spheroidization mechanism of the fine {alpha}{sub 2} plates, is not clarified yet. The purpose of this study is to investigate the microstructural development of the massively transformed {gamma} structure during isothermal aging, and to discuss the {gamma} {yields} {alpha}({alpha}{sub 2}) phase transformation.

• OSTI ID: 455188
• Journal Information: Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 5 Vol. 36; ISSN 1359-6462; ISSN SCMAF7
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AGING
ALUMINIUM ALLOYS
EXPERIMENTAL DATA
GRAIN GROWTH
MICROSTRUCTURE
PHASE TRANSFORMATIONS
PRECIPITATION
TITANIUM ALLOYS