Devitrification behaviour of rapidly solidified Al_87Ni_7Cu_3Nd_3 amorphous alloy prepared by melt spinning method  

作　　者：肖于德 李敏 钟掘 黎文献 马正青 

机构地区：[1]School of Materials Science and Engineering Central South University [2]School of Mechanical and Electrical Engineering, Central South University

出　　处：《Journal of Central South University of Technology》2007年第3期285-290,共6页中南工业大学学报（英文版）

基　　金：Project(2005-5) supported by the Postdoctoral Foundation of Central South University, China;Project(2005038560) supported by the Postdoctoral Science Foundation of China

摘　　要：Rapidly solidified Al87Ni7Cu3Nd3 amorphous alloy was prepared by using melt spinning. Its calorimetric behavior was characterized by using differential scanning calorimeter in a continuous or isothermal heating mode. phase transformation was investigated, with a special interest in primary crystallization, by using an in-situ examination of X-ray diffractometry （XRD） and high resolution transmission electron microscopy （HRTEM）. The results show that, the whole devitrification of rapidly solidified Al87NiyCu3Nd3 amorphous alloy involves two main processes of primary crystallization and secondary crystallization that consist mainly of two reactions. For primary crystallization, the apparent activation energies, EIso and EKis and growth activation energies Eg are about 153, 166 and 288 kJ/mol, respectively. The interdiffusion of Al atoms is a rate-controlled step of formation of the a（Al） particles, but slow diffusion of Ni and Nd atoms plays a significant role in retarding growth of the α （Al） particles. For secondary crystallization, EIso, EKis and Eg of the first reaction are about 291,208 and 290 kJ/mol, and those of the second reaction are about 367, 269 and 372 kJ/mol. The two reactions of secondary crystallization are controlled mainly in an interface-controlled three-dimensional mode, depending mainly on slow diffusion of Ni and Nd atoms.Rapidly solidified Al87Ni7Cu3Nd3 amorphous alloy was prepared by using melt spinning. Its calorimetric behavior was characterized by using differential scanning calorimeter in a continuous or isothermal heating mode. phase transformation was investigated, with a special interest in primary crystallization, by using an in-situ examination of X-ray diffractometry (XRD) and high resolution transmission electron microscopy (HRTEM). The results show that, the whole devitrification of rapidly solidified Al87Ni7Cu3Nd3 amorphous alloy involves two main processes of primary crystallization and secondary crystallization that consist mainly of two reactions. For primary crystallization, the apparent activation energies, EIso and EKis and growth activation energies Eg are about 153, 166 and 288 kJ/mol, respectively. The interdiffusion of Al atoms is a rate-controlled step of formation of the α(Al) particles, but slow diffusion of Ni and Nd atoms plays a significant role in retarding growth of the α (Al) particles. For secondary crystallization, EIso, EKis and Eg of the first reaction are about 291, 208 and 290 kJ/mol, and those of the second reaction are about 367, 269 and 372 kJ/mol. The two reactions of secondary crystallization are controlled mainly in an interface-controlled three-dimensional mode, depending mainly on slow diffusion of Ni and Nd atoms.

关 键 词：rapid solidification Al-rich amorphous alloy CRYSTALLIZATION nucleation and growth 

分 类 号：O753[理学—晶体学]