Pulse current auxiliary forging of sintered TiAl alloys based on the investigation of dynamic recrystallization and phase transformation

Journal Article · Mon Jan 15 04:00:00 EST 2018 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2017.11.028· OSTI ID:22804855

Shi, Chengcheng; Zhang, Kaifeng ^[1]; Jiang, Shaosong ^[2]; Huang, Zhenhan ^[1]

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1. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)
2. National Key Laboratory of Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001 (China)

Highlights: • DRX kinetics model of sintered near γ TiAl alloy was established. • DRX process was accompanied by twinning when compressed at 1125 °C/0.1 s{sup − 1}. • Hot deformation has a promotion to the phase transformation of γ → α. - Abstract: Pulse current auxiliary forging is a new and efficient way to fabricate high performance TiAl based alloys. Dynamic recrystallization (DRX) and phase transformation have a pronounced effect on the subsequent deformability of TiAl based alloys. Hence, the dynamic recrystallization kinetics were determined at the temperature range of 1125–1275 °C and strain rate range of 0.1–0.001 s{sup − 1}. In addition, the DRX mechanism and phase transformation of TiAl based alloys were investigated to model the microstructure evolution in order to provide guidance for the pulse current auxiliary forging process. When the specimens were compressed at 1125 °C/0.1 s{sup − 1}, twinning played an important role in the DRX process. With increasing deformation temperature, the microstructure transformed from near gamma into duplex microstructure. In addition, according to the kinetics of dynamic recrystallization and phase transformation, fully DRXed TiAl based alloys were fabricated through pulse current auxiliary forging. The as-forged TiAl-based alloys show good superplastic performance with an elongation over 410%.

• OSTI ID: 22804855
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 135; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM COMPOUNDS
BINARY ALLOY SYSTEMS
ELONGATION
MICROSTRUCTURE
PHASE TRANSFORMATIONS
RECRYSTALLIZATION
TEMPERATURE RANGE 1000-4000 K
TITANIUM COMPOUNDS