Mechanical properties of porous ITM alloy

Mechanical characteristics of porous ITM are assessed for the use as metallic substrate in solid oxide fuel cell stacks. Elastic modulus and Poisson's ratio are determined using an impulse excitation technique, thermal expansion is measured with an optical dilatometer, and ultimate tensile strength and creep are measured in a tensile set-up. Data are compared and discussed with respect to the properties of dense ITM. The results indicate that the coefficient of thermal expansion is not affected by the porosity, while the Poisson's ratio is only affected to a minor extent. The coefficient of thermal expansion and elastic modulus appear to be influenced by a ferromagnetic-paramagnetic transition. The elastic modulus of the porous material is, as expected, reduced due to smaller effective area of the porous specimens. The largest change compared to the behavior observed for the dense ITM is seen for the ultimate tensile strength. The large creep stress exponent of the dense and porous material over a wide stress range is a result of the dispersed nano-sized Y-rich phase, however, a change in creep mechanism is indicated for the porous ITM for the low-stress region.