High temperature compression properties of open-cell Ni-20Cr foams produced by impregnation

摘要

The mechanical properties of open-cell Ni-20Cr foams were studied by uniaxial compression tests, which were performed at a strain rate of 10~(-3) s~(-1) at ambient temperature, 250 ℃, 400 ℃ and 550 ℃ respectively. Then, the effect of temperature on the mechanical properties of these foams was analyzed. It was found that both the compressive strength and energy absorbed by Ni-20Cr foam at elevated temperatures became lower than those at room temperature. The compressive strength changed with temperatures in a form of parabola, which satisfied the model derived from Gibson-Ashby model combined with Kocks' kinetic model. A multi-parameter phenomenological elasto-plastic constitutive model was modified to take the temperature effect into consideration. The relationships between model parameters and temperature were determined. The fitting stress-strain curves of the model were in good agreement with me experimental results.