Dynamic tensile behavior of PM Ti-47Al-2Nb-2Cr-0.2W intermetallics at elevated temperatures
(1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. School of Materials Science and Engineering, Hefei University of Technology, Hefei 230027, China;
3. Yuanmeng Precision Technology (Shenzhen) Institute, Shenzhen 518055, China)
2. School of Materials Science and Engineering, Hefei University of Technology, Hefei 230027, China;
3. Yuanmeng Precision Technology (Shenzhen) Institute, Shenzhen 518055, China)
Abstract: Split Hopkinson Tension Bar (SHTB) experiments were conducted to explore the dynamic mechanical behavior and deformation mechanism of powder metallurgical (PM) Ti-47Al-2Nb-2Cr-0.2W (at.%) intermetallics with near lamellar (NL) and duplex (DP) microstructures. Results show that, under dynamic loading, the high temperature strength of the PM TiAl intermetallics is higher than that under quasi-static loading, and the ductile to brittle transition temperature (DBTT) increases with the increase of strain rate. Formation of twinning and stacking faults is the main deformation mechanism during dynamic loading. The work hardening rates of the PM TiAl intermetallics are nearly insensitive to strain rate and temperature at high strain rates (800-l600 s-1) and high temperatures (650-850 °C). Zerilli-Armstrong model is successfully used to describe the dynamic flowing behavior of the PM TiAl intermetallics. In general, the PM TiAl intermetallics are found to have promising impact properties, suitable for high-temperature and high-impact applications.
Key words: TiAl intermetallics; deformation mechanism; powder metallurgy; dynamic deformation; Split Hopkinson Bar