添加微量Sc的Al-Y-Ni非晶合金熱穩定性與機械性質研究

本研究以單輥熔射旋淬法及熔射法分別製備 (Al87Y8Ni5)100-XScX (X =0，0.5，1.0，1.5及 2.0 at.%)之薄帶以及直徑為1 mm棒材，以期藉由添加鈧(Sc)來改善鋁釔鎳非晶合金之形成能力，並保持良好的機械性質。當鈧添加至2.0 at.%時，可由XRD及SEM觀察合金薄帶皆具有非晶質結構，薄帶硬度值隨著鈧的添加量增加而上升(350 Hv ~ 430 Hv)；在非晶熱穩定性上，鋁釔鎳隨著鈧的添加量上升，結晶化溫度有越往高溫移動之趨勢；而利用Kissinger equation所獲得之結晶活化能顯示，隨著鈧添加量由0 at.%上升到2 at.%，結晶活化能從159 kJ/mole上升至241 kJ/mole。由鋁釔鎳鈧的棒材，可以觀察到在靠近銅模位置的冷卻速率最快，結晶化較不明顯，但硬度值較薄帶略小，約為340 Hv；而距離銅模較遠的位置冷速最慢，出現明顯的結晶，硬度值則約為210 Hv，硬度明顯降低許多。由實驗中可以了解隨著鈧的添加量上升，材料中產生更多的奈米晶，因此達到細晶強化之效果，故機械性質隨之上升。

關鍵字

熱穩定性；機械性質；結晶活化能

並列摘要

Effects of glass forming ability by scandium addition to Al-Y-Ni amorphous alloy were investigated in this study. The alloy ribbons of (Al87Y8Ni5)100-xScx (X=0, 0.5, 1.0, 1.5 and 2.0 at.%) were prepared by single roller melt-spinning method and spray method, and alloy rods were prepared by inductance casting. With up to 2 at.% addition of scandium, the ribbon was confirmed amorphous by XRD and SEM observations. The hardness increased with the addition of scandium and ranged between 350 Hv and 440 Hv. Thermal stability of amorphous nickel-yttrium aluminum ribbons appeared to rise with the concentration of scandium. The crystallization temperature of ribbons also increased with scandium addition. 2 at.% of scandium was also found to increase the crystallization activation energy from 159 kJ/mole to 241 kJ/mole. For rods, the highest cooling rate is obtained at the surface near the copper mold where no significant crystallization was observed and microhardness of 340Hv was achieved. Crystallization increased with the distance away from the copper mold where the microhardness reduces to about 220Hv.The percentage of nano-crystallites increased with the addition of scandium and gave rise to grain refinement and increased mechanical properties.

並列關鍵字

Thermal Stability ； Mechanical Properties ； Crystallization Activation Energy

參考文獻

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國際替代計量

添加微量Sc的Al-Y-Ni非晶合金熱穩定性與機械性質研究

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