微量Ce對Al-Y-Ni非晶合金晶化行為及顯微結構之研究

Abstract

The 30~35 μm thickness alloy ribbons of (Al87Y8Ni5)100-xCex(x=0,1 at.%) were produced by single roller melt-spinning method. The XRD spectra of (Al87Y8Ni5)100-xCex(x=0,1 at.%) alloy ribbons consisted of only broad diffraction peaks without any sharp Bragg peaks, and SEM-SE image has no crystallization shows, indicating they are amorphous in structure. The alloy ribbons by DSC measure the thermal properties, The (Al87Y8Ni5)99Ce1 alloy ribbons demonstrates a glass transition temperature (Tg)at 483.2 K, and its ΔTx is 41.3 K. In non-isothermal the alloy ribbons of x=0 at.% has the highest microhardness of 570.8 Hv at the annealing temperature is 592 K. And the alloy ribbons of x=1 at.% has the highest microhardness of 592.8 Hv at the annealing temperature is 650 K. In isothermal the alloy ribbons of x=0 at.% has the highest microhardness of 551.5 Hv at the annealing time is 30 min. And the alloy ribbons of x=1 at.% has the highest microhardness of 602.2Hv at the annealing time is 80 min. In annealing process, because in the ribbons of Al nanocrystalline precipitation, thereby increasing the microhardness. In non-isothermal and isothermal annealing the alloy ribbons of x=0 at.%, the α-Al、Al3Y 、AlNi and unknow metastable phase were then precipitated in sequence. And the alloy ribbons of x=1 at.%, the α-Al、Al3Y、AlNi、Al3Ce、AlCeNi and unknow metastable phase were then precipitated in sequence. At x=0 at.%, the activation energy for crystallization was 163 kJ/mol, x=1 at.%, the activation energy for crystallization was 189 kJ/mol. Therefore, addition of Ce element, can improve the thermal stability of the alloy.