Mechanical Strengths, Thermal Stability and Electrical Resistivity of Aluminum-Rare Earth Metal Binary Amorphous Alloys

Aluminum-rich amorphous alloys in Al–Ln (Ln=lanthanide element) binary systems were formed in the range of 7 to 16 at% Ln by melt spinning. The amorphous alloys exhibit good bending ductility in the entire compositional ranges. With increasing Ln content, the crystallization temperature, Vickers hardness number, tensile strength and electrical resistivity at room temperature of the Al–Ln amorphous alloys increase from 434 to 534 K, 150 to 270, 360 to 870 MPa and 48 to 109 μΩcm, respectively; thus there are no systematic changes of their values with the change in the atomic number of the Ln metals. It is noteworthy that the Al–Ln amorphous alloys have a high tensile strength of 870 MPa which exceeds the highest strength obtained with conventional Al-base crystalline alloys. The glass formation and compositional dependence of the amorphous binary alloys are explained on the basis of the assumption that the attractive bonding nature between Al and Ln metals is dominant rather than the volume mismatch resulting from the difference in atomic size.