High-temperature mechanical responses of the polyimide at a high strain rate

Abstract

Abstract Polyimide is one of the best super engineering materials in the world at present, and it is required to have high bearing capacity at specific temperature and strain rate because of the application environment. Therefore, the compressive mechanical properties of polyimide at different strain rates (10−3 s−1–4000 s−1) and temperatures (20 °C–350 °C) were researched. The experimental results show the sensitivity to temperatures and strain rates. However, the strain hardening rates decrease with the increase in temperature, and even the flow stress under dynamic compression is lower than that under quasi-static compression at large strain. In addition, it is found that the cracks show different characteristics under 4000 s−1 at different loading temperatures, which are tiny cracks at room temperature and deep and wide cracks due to the coupling of strain rate and thermal at 350 °C.