Compression Mechanical Properties of FeAl Intermetallic Compound Porous Material

Fe-40at%Al intermetallic compound porous material prepared by an element mixture partial diffusion-reactive synthesis-sintering method was researched by a uniaxial compression test in order to analyze its characteristics of stress-strain curve and mechanical properties affected by porosity and reveal its microscopic fracture mechanism in compression by scanning electron microscope test. Results show that the compressive stress-strain curves of the FeAl porous material can be divided into four stages: elasticity, yielding, strengthening and failure, where the larger the porosity (i.e., the lower the relative density), the more obvious the nonlinear elasticity. With the increase of the porosity, the compressive yield strength changes little, while the elastic modulus and compressive strength significantly decrease. The characteristic of the fracture surface is of brittle fracture in macroscopy and of intergranular fracture in microscopy. Comparing the theoretical values and experimental values of the elastic modulus of FeAl porous material, it is found that the micromechanical model of heterogeneous Plateau porous structure is more accurate for predicting the effective elastic modulus of the medium-density porous materials but not for the high-density ones.