Strain rate sensitivity of open-cell titanium foam at elevated temperature

Compressive deformation of open-cell pure titanium foams with the porosity of 60% has been studied at different compression speeds from 0.1 to 10 mm/min and temperatures from 300 to 673 K. Stress-strain curves showed linear elastic, plateau and densification regions which are typical characteristics of metal foams. Both the flow stress and the energy absorption increase with increasing the strain rate and with decreasing the temperature. Strain rate sensitivity exponents of the titanium foam at 300, 473 and 673 K were 0.018, 0.042 and 0.021, respectively. Apparent activation energy of the titanium foam was 72.6 kJ/mol. These values are close to those of dense commercially pure titanium. These results indicate that the thermally activated kinetics of the titanium foam mainly depends on the characteristics of the base material. In addition, XRD analysis showed the excellent oxidation resistance of the titanium foam. Present study revealed that titanium foams have a potential of lightweight structural material even at elevated temperature up to 673 K.