PRECIPITATION BEHAVIOR OF GP ZONES DURING AGEING PROCESS OF Mg-Zn ALLOY
Received date: 2009-10-26
Revised date: 2010-03-10
Online published: 2010-05-11
Supported by
Supported by National Natural Science Foundation of China (Nos.50731002 and 50671009) and Specialized Research Fund for the Doctoral Program of Higher Education (No.20060008015)
The age--hardening behavior of the Mg-1.9Zn (atomic fraction, %) alloy, morphologies of GP zones and temperature range of GP zone precipitation in the alloy were investigated by micro-hardness, XRD and TEM. The results show that the Zn atoms segregation occurs in the super-saturated solid solution, forming GP zones with different shapes during ageing process at 343 and 383 K; while at 423 K the age-hardening peak occurs earlier but no typical GP zone appeared. Using the thermodynamic parameters of the Mg-Zn system, the Gibbs free energy relations of the Mg-based solid solution phase were calculated, indicating the existences of the metastable miscibility gap and the solute atoms segregation in the super-saturated solid solution. With the reported data and the present experimental results, the ranges of composition and aging temperature for GP zone precipitation in the Mg-Zn alloy were determined.
Key words： Mg-Zn alloy; low temperature ageing; GP zone; thermodynamic analysis
YU Xiao-Liang , LI Zhang-Rong , GUO Cui-Ping , DU Zhen-Min , HE Wei . PRECIPITATION BEHAVIOR OF GP ZONES DURING AGEING PROCESS OF Mg-Zn ALLOY[J]. Acta Metall Sin, 2010 , 46(5) : 575 -580 . DOI: 10.3724/SP.J.1037.2009.00708
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