Thermal Stability Of Al-Base Alloy And Glass Forming Ability Of Rare Earth Base Alloy

Aluminum base nano-crystal and amorphous alloys with excellent properties, such as high thermal stability, high strength, excellent bending ability and corrosion resistance, have potential applications in aviation and space flight. Rare earth base alloy with special characteristic make them potential candidates for function materials.In this paper, mechanical alloy was employed to investigate the formation of nanocrystslline and amorphous alloy of Al-Fe-Zr-Ce. And melt-spin was employed to study of amorphous-forming of RE-Fe-Zr-Al alloy. The evolution of microstructure, morphology and the thermal stability of alloys were investigated by XRD, DSC and SEM. The influence of the content of Fe and Zr to the amorphous forming of Gd-base alloys are also studied. A fully amorphous alloy was formed for the mixture powders of Al₈₂Fe₅Zr₅Ce₈ after milling for 200h and with good thermal stability. The crystallization activation energy of the amorphous alloy for the two sequent peaks estimated with the Kissinger equation are E_tx1=442.3kJ/mol, E_tp1=475.6kJ/mol,E_tx2=419.9kJ/mol and E_tp2=408.8kJ/mol respectively. After 15h-milling, Gd₆₀Fe_30-XZr_XAl₁₀(x=5,10,20) are amorphous. Gd₆₀Fe₂₀Zr₁₀Al₁₀ began to crystallize after 23h-milling. The amorphous formation and stability of amorphous structure of Gd₆₀Fe_30-XZr_XAl₁₀ (x=5,10,20) boost up with the increase of Fe. The Miedema theory was used to predict the amorphous forming composition range of two alloy systems Al-Fe-Zr-Ce and Gd-Fe-Zr-Al. The predictions are in reasonable accord with experiment results.