Mechanical Properties of Fe<sub>2</sub>Al<sub>5</sub> and FeAl<sub>3</sub> Intermetallic Phases at Ambient Temperature

Abstract

In the present study, hardness, elastic modulus and fracture toughness of η-Fe2Al5 (oC24 structure) and θ-FeAl3 (mS102 structure) single phase alloys have been examined by various indentation methods. The average hardness of η and θ phases measured by Vickers indentation are 8.5 GPa and 7.8 GPa, respectively. The hardness variations are approximately 20% in η phase and 15% in θ phase, which are associated with their orientation dependence. A trend was found that the hardness becomes lower close to the [001] indentation direction in both phases. The elastic moduli of η and θ phases measured by nanoindentation are higher than the modulus of pure Fe (about 200 GPa). The fracture toughness of η and θ phases measured by indentation fracture method are 1.38 and 1.27 MPa·m1/2, respectively. The anisotropy of their toughness was not found in the present measurements.