Phase transformations of the L12-Ti3Al phase in γ-TiAl alloy

Shouzhen Cao; Shulong Xiao; Yuyong Chen; Lijuan Xu; Xiaopeng Wang; Jianchao Han; Yi Jia

doi:10.1016/j.matdes.2017.02.047

Phase transformations of the L1₂-Ti₃Al phase in γ-TiAl alloy

Shouzhen Cao
, Shulong Xiao^*
, Yuyong Chen
, Lijuan Xu
, Xiaopeng Wang
, Jianchao Han
, Yi Jia

^*Corresponding author for this work

Harbin Institute of Technology
Harbin Institute of Technology
Taiyuan University of Technology

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

41 Scopus citations

Abstract

A new phase L1₂-Ti₃Al was found in the Ti-46Al-6Nb alloy after rapid-cooling and then annealing at 850 °C for 5 h. The transformation kinetics involving the L1₂ phase were observed by transmission electron microscopy (TEM): The plate-like L1₂ phase precipitates in the massive γ (γ_m) phase and then partially transforms into α₂ or B2 phase; the transformations of bulk α₂ (α_b) → L1₂/L1₂ → γ were also observed to form a fine lamellar structure with an average interlamellar spacing < 20 nm. The orientation relationships between γ, α₂ and L1₂ phases were confirmed by TEM observation and crystallographic calculation, which are (001)γ // (001)L1₂, [010]γ // [010]L1₂, [100]γ // [100]L1₂ and (0001)α₂ // {111}L1₂, 〈112¯0〉α₂ // 〈11¯0〉L1_2. The L1₂ phase was also observed in Ti-the 47Al alloy after the quenching-annealing process. Thermodynamic analysis of the transformations indicates that the γ → L1₂ transformation is extremely susceptible to temperature changes while transformations between the α₂ and L1₂ phases are not.

Original language	English
Pages (from-to)	61-68
Number of pages	8
Journal	Materials and Design
Volume	121
DOIs	https://doi.org/10.1016/j.matdes.2017.02.047
State	Published - 5 May 2017
Externally published	Yes

Keywords

Crystallographic
L1-TiAl phase
Phase transformation
Thermodynamic
Titanium aluminides

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10.1016/j.matdes.2017.02.047

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@article{ef87b21be775471991c8dda3c69ab0cf,

title = "Phase transformations of the L12-Ti3Al phase in γ-TiAl alloy",

abstract = "A new phase L12-Ti3Al was found in the Ti-46Al-6Nb alloy after rapid-cooling and then annealing at 850 °C for 5 h. The transformation kinetics involving the L12 phase were observed by transmission electron microscopy (TEM): The plate-like L12 phase precipitates in the massive γ (γm) phase and then partially transforms into α2 or B2 phase; the transformations of bulk α2 (αb) → L12/L12 → γ were also observed to form a fine lamellar structure with an average interlamellar spacing < 20 nm. The orientation relationships between γ, α2 and L12 phases were confirmed by TEM observation and crystallographic calculation, which are (001)γ // (001)L12, [010]γ // [010]L12, [100]γ // [100]L12 and (0001)α2 // \{111\}L12, 〈112¯0〉α2 // 〈11¯0〉L12. The L12 phase was also observed in Ti-the 47Al alloy after the quenching-annealing process. Thermodynamic analysis of the transformations indicates that the γ → L12 transformation is extremely susceptible to temperature changes while transformations between the α2 and L12 phases are not.",

keywords = "Crystallographic, L1-TiAl phase, Phase transformation, Thermodynamic, Titanium aluminides",

author = "Shouzhen Cao and Shulong Xiao and Yuyong Chen and Lijuan Xu and Xiaopeng Wang and Jianchao Han and Yi Jia",

note = "Publisher Copyright: {\textcopyright} 2017",

year = "2017",

month = may,

day = "5",

doi = "10.1016/j.matdes.2017.02.047",

language = "英语",

volume = "121",

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T1 - Phase transformations of the L12-Ti3Al phase in γ-TiAl alloy

AU - Cao, Shouzhen

AU - Xiao, Shulong

AU - Chen, Yuyong

AU - Xu, Lijuan

AU - Wang, Xiaopeng

AU - Han, Jianchao

AU - Jia, Yi

PY - 2017/5/5

Y1 - 2017/5/5

N2 - A new phase L12-Ti3Al was found in the Ti-46Al-6Nb alloy after rapid-cooling and then annealing at 850 °C for 5 h. The transformation kinetics involving the L12 phase were observed by transmission electron microscopy (TEM): The plate-like L12 phase precipitates in the massive γ (γm) phase and then partially transforms into α2 or B2 phase; the transformations of bulk α2 (αb) → L12/L12 → γ were also observed to form a fine lamellar structure with an average interlamellar spacing < 20 nm. The orientation relationships between γ, α2 and L12 phases were confirmed by TEM observation and crystallographic calculation, which are (001)γ // (001)L12, [010]γ // [010]L12, [100]γ // [100]L12 and (0001)α2 // {111}L12, 〈112¯0〉α2 // 〈11¯0〉L12. The L12 phase was also observed in Ti-the 47Al alloy after the quenching-annealing process. Thermodynamic analysis of the transformations indicates that the γ → L12 transformation is extremely susceptible to temperature changes while transformations between the α2 and L12 phases are not.

AB - A new phase L12-Ti3Al was found in the Ti-46Al-6Nb alloy after rapid-cooling and then annealing at 850 °C for 5 h. The transformation kinetics involving the L12 phase were observed by transmission electron microscopy (TEM): The plate-like L12 phase precipitates in the massive γ (γm) phase and then partially transforms into α2 or B2 phase; the transformations of bulk α2 (αb) → L12/L12 → γ were also observed to form a fine lamellar structure with an average interlamellar spacing < 20 nm. The orientation relationships between γ, α2 and L12 phases were confirmed by TEM observation and crystallographic calculation, which are (001)γ // (001)L12, [010]γ // [010]L12, [100]γ // [100]L12 and (0001)α2 // {111}L12, 〈112¯0〉α2 // 〈11¯0〉L12. The L12 phase was also observed in Ti-the 47Al alloy after the quenching-annealing process. Thermodynamic analysis of the transformations indicates that the γ → L12 transformation is extremely susceptible to temperature changes while transformations between the α2 and L12 phases are not.

KW - Crystallographic

KW - L1-TiAl phase

KW - Phase transformation

KW - Thermodynamic

KW - Titanium aluminides

UR - https://www.scopus.com/pages/publications/85013322036

U2 - 10.1016/j.matdes.2017.02.047

DO - 10.1016/j.matdes.2017.02.047

M3 - 文章

AN - SCOPUS:85013322036

SN - 0264-1275

VL - 121

SP - 61

EP - 68

JO - Materials and Design

JF - Materials and Design

ER -

Phase transformations of the L1₂-Ti₃Al phase in γ-TiAl alloy

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