Formation of non-equilibrium phases and associated structural transition in the Pd-Ta system induced by ion beam mixing  

作　　者：ZHAO Man DAI Ye LI JiaHao LIU BaiXin 

机构地区：[1]Advanced Materials Laboratory, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China

出　　处：《Science China(Technological Sciences)》2011年第3期676-681,共6页中国科学（技术科学英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No. 50971072);the Ministry of Science and Technology of China (Grant No. 2006CB605201);the Administration of Tsinghua University

摘　　要：For the Pd-Ta system characterized by a negative heat of formation of -78 kJ/mol, 200 keV xenon ion beam mixing with nano-sized Pd-Ta multilayered films was conducted to study the non-equilibrium phase formation. The results showed that uniform amorphous alloys can be formed within a composition range of 25 at%-78 at% Ta, which falls in the maximum possible amorphization range of 22 at%-80 at% Ta predicted by the empirical model. Moreover, two metastable crystalline phases both of FCC structure, yet with different lattice constants were obtained. Interestingly, a self-assembled fractal pattern was observed in the Pd52Ta48 multilayered films after irradiation to a dose of 1×1015 Xe+/cm2 and its dimension was determined to be 1.75±0.05. The possible mechanisms for the formation of amorphous and metastable crystalline phases as well as for the growth of the fractal pattern were discussed.

关 键 词：amorphous phase Pd-Ta alloy ion beam mixing metastable crystalline phase FRACTAL 

分 类 号：TQ174.758[化学工程—陶瓷工业] TG131[化学工程—硅酸盐工业]