Determination of dynamic behavior of materials at elevated temperatures and high strain rates using Hopkinson bar
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摘要: 描述了一种利用Hopkinson杆装置确定在高温(温度可高达1 173 K)、高应变率下材料动态性能的试验方法。在试样加温过程中,试样不与入射杆及透射杆接触。当试样加热到预定温度时,气压驱动同步组装系统,推动透射杆及试样,使得应力波到达入射杆与试样接触面时,入射杆、试样及透射杆紧密接触。利用以上系统,完成了连铸单晶铜及上引法连铸多晶铜从室温到1 085 K范围内的应力应变曲线。测试结果表明,不论是上引法连铸多晶铜还是连铸单晶铜,流动应力随温度的升高而下降,在温度低于585 K时,材料的应变硬化率明显大于在温度高于585 K时的应变硬化率。Abstract: 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.
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Key words:
- solid mechanics /
- flow stress /
- Hopkinson bar /
- high temperature /
- high strain rate /
- strain hardening
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