Microstructure and room-temperature mechanical properties of crystalline and amorphous FeAl based melt spun ribbons

Abstract The microstructure and mechanical properties of crystalline Fe81%-Al19% and amorphous Fe72%-Al14%-B14% ribbons obtained by the melt spinning technique are studied. A different grain size in each surface of the crystalline ribbon has been found. This is caused by the temperature gradient originated by the manufacturing process. The micro-hardness and the Young's modulus were evaluated by instrumented micro-indentation (P-h curves) and conventional tensile test. The results show different Vicker's hardness on each surface for each of the ribbons, being these values greater in the amorphous ribbon than in the crystalline one. The values of the Young's modulus are 133 ± 11 GPa and 210 ± 20 GPa for the crystalline and amorphous ribbon respectively which are in good agreement with the theoretical values obtained by the mix rule. The surface fracture shows a brittle-like aspect with presence of cleavage in the Fe81%-Al19% ribbon and small localized ductile behavior before reaching the fracture. In the other hand, in the Fe72%-Al14%-B14% ribbon, the surface fracture characteristics reveal a fragile fracture and the presence of chevron marks. There is a concordance between the mechanical behavior and the micro-mechanism responsible for the fracture.