High Nb–TiAl Intermetallic Blades Fabricated by Isothermal Die Forging Process at Low Temperature

Metals

Xiaopeng Wang¹  Haitao Zhou²  Yuyong Chen²  Fantao Kong²  Wenchen Xu²  Peng Xu² 

[1] Center of Analysis and Measurement, Harbin Institute of Technology, Harbin 150001, China;National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, China;

关键词: high Nb–TiAl alloy;    isothermal die forging;    effective stress;    blade;    microstructure;   

DOI  :  10.3390/met10060757

来源: DOAJ

【 摘 要 】

In this study, the isothermal die forging process of high Nb–TiAl (Ti-44Al-8Nb-0.2W-0.2B-Y, at.%) alloy blades was simulated using the ABAQUS V6.11 software and the blades were fabricated successfully. The influence of a low forging temperature (lower than 1000 °C) and strain rate on the distributions of effective strain and stress were analyzed. The results indicate that the effective strain exhibits negative temperature sensitivity and positive strain rate sensitivity. The stress exponent (n = 3.02) and the apparent activation energy (Q = 293.381 kJ/mol) of the present alloy suggests that this as-forged high Nb–TiAl alloy exhibits good deformability at low temperatures. With the reduction in strain rate and the increase in forging temperature, the effective stress decreases. Finally, high-quality high Nb–TiAl alloy blades were fabricated using an isothermal die forging technology at a rate of 0.01 mm/s and temperature of 950 °C, chosen on the basis of the simulations results. Scanning electron microscopy (SEM) and electron back scatter diffraction (EBSD) results indicated that the center of the TiAl alloy blade possessed a duplex microstructure, consisting of remnant lamellar colonies and recrystallized γ/B2 grains. The refined α₂ laths showed a typical forging flow line feature in the edge position, whereas the γ laths had broken down and recrystallized.

【 授权许可】

Unknown