Mechanical Properties of Fe2Al5 and FeAl3 Intermetallic Phases at Ambient Temperature

In the present study, hardness, elastic modulus and fracture toughness of eta-Fe2Al5 (oC24 structure) and theta-FeAl3 (mS102 structure) single phase alloys have been examined by various indentation methods. The average hardness of eta and theta phases measured by Vickers indentation are 8.5 GPa and 7.8 GPa, respectively. The hardness variations are approximately 20 % in ri phase and 15 % in theta 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 eta and theta phases measured by nanoindentation are higher than the modulus of pure Fe (about 200 GPa). The fracture toughness of eta and theta phases measured by indentation fracture method are 1.38 and 1.27 MPa.m(1/2), respectively. The anisotropy of their toughness was not found in the present measurements.