Determination of dynamic behavior of materials at elevated temperatures and high strain rates using Hopkinson bar

The Hopkinson bar technique with a furnace and a driving mechanism is utilized to determine the dynamic property of materials at elevated temperature and high strain rates. The specimen is heated by a furnace independently. While the temperature in specimen reaches the desired temperature, a driving mechanism shifts the transmission bar and the specimen to contact the incident bar, so that the transmission bar, the specimen and incident bar fully contact each other just before the stress wave reaches the interface between incident bar and specimen. The dynamic properties of single crystal copper and polycrystal copper at the temperature range from room temperature to 1 085 K are tested. The results show that the flow stress of both materials decreases with increase of temperature, and strain hardening rates at a temperature below 585 K are greater than that at the temperature above 585 K.