(Ti,Zr,Hf)-(Cu,Ni,Ag)-Al多组元合金体系的机械驱动非晶化

研究了由前过渡族金属和后过渡族金属按照等原子比替代的(Ti0.33Zr0.33Hf0.33)50(Ni0.33Cu0.33Ag0.33)40Al10多组元合金在机械研磨作用下的非晶化转变,并与由熔体急冷制备的同一成分玻璃态合金进行了对比.两种途径获得的玻璃态相似.在机械研磨的稳态产物中,仍残留有少量尺寸小于30 nm的晶体相颗粒,即非晶化转变未能完全实现.机械研磨形成的非晶相表现有明确的玻璃转变和约80 K宽的过冷液态温度区间,晶化过程分两步进行,第一步晶化转变完成后,剩余的非晶相亦具有玻璃态行为,呈现另一玻璃转变及约100 K宽的过冷液态温度区间.

MECHANICALLY--DRIVEN AMORPHIZATION IN A (Ti, Zr, Hf)--(Cu, Ni, Ag)--Al MULTICOMPONENT ALLOY SYSTEM

The glass formation under high-energy ball milling was investigated for a (Ti0.33Zr0.33Hf0.33)5o(Ni0.33Cu0.33Ag0.33)40Al10 high-order alloy system. For comparison, the glassy ribbon with the same composition was prepared using melt-spinning (MS) method as well. Structural features of the samples were characterized using X-ray diffraction, ransmission electron microscopy and differential scanning calorimetry. Mechanical alloying (MA) results in a formation of glassy alloy similar to that obtained by MS. But, the glass formation is incomplete and a small amount of unreated crystallites smaller than 30 nm in size still remains in the final product. Like the melt-spun glass, the ball-milled glassy alloy also exhibits a distinct glass transition and a wide supercooled liquid region of about 80 K. Crystallization of the glassy alloy is a two-step process, regardless of the synthesis routes. After the primary crystallization is completed, the remaining amorphous phase shows a detectable glass transition and a large supercooled liquid region of about 100 K.