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

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 degrees C, 400 degrees C and 550 degrees C 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 the experimental results. (C) 2015 Elsevier Ltd. All rights reserved,