Formation, Thermal Stability and Mechanical Properties of New Amorphous Al<SUB>89</SUB>Fe<SUB>10</SUB>Zr<SUB>1</SUB> Alloy

Abstract

A new amorphous alloy with high tensile strength and good bending ductility was fabricated from a melt-spun Al 89 Fe 10 Zr 1 alloy without the lanthanide (Ln) element. The Al content for glass formation is believed to be the highest in the Ln-free Al-based alloys. The as-quenched phase changes to a mixed structure of amorphous and fcc-Al phases with decreasing Fe content to 7-9 at%, and the particle size of the Al phase is 40 nm at 7%Fe, 10 nm at 8%Fe and 5 nm at 9%Fe. The mixed phase alloys also have good bending ductility. The tensile fracture strength (σ f ) is 1050 MPa for the amorphous Al 89 Fe 10 Zr 1 alloy and decreases to 720-1000 MPa for the mixed phase alloys with 7 to 9%Fe concentrations. The amorphous alloy crystallizes by two-stage reactions of Am→Am+Al→Al+Al 3 Zr+Al 13 Fe 4 and the onset temperature of each exothermic reaction is 460 and 650 K. The σ f of the amorphous alloy increases to 1220 MPa without detriment to good ductile nature by the precipitation of about 20 vol% Al phase. The achievement of high σ f combined with good bending ductility in the Ln-free Al-Fe-Zr alloys with the high Al concentration of about 90% is important as a new basic alloy system to produce a high-strength Al-based alloy with low specific weight and inexpensiveness.