Structural Relaxation of Ti-based Bulk Metallic Glasses
The enthalpy relaxation behavior of Ti41.5Cu37.5Ni7.5Zr2.5Hf5 Sn5 Si1 bulk metallic glass (BMG) was investigated in this study. It is found that relaxation behavior follows the general characteristics for amorphous materials: the annealing time dependence of recovery enthalpy follows a stretched exponential function with the mean relaxation time obeying an Arrhenius law. In addition,the equilibrium recovery enthalpy AH?, mean relaxation time t and stretching exponent β are annealing temperature dependent,and the higher the annealing temperature, the lower the values of △H∞T, τ and higher of β The activation energy for enthalpy relaxation is calculated to be 3. 06 eV. suggesting that the governing mechanism for the enthalpy relaxation process of this alloy is the rearrangement involving the collective hopping mechanism for the small and medium size atoms. Two parameters,βx and τR, representing the stretching exponent and the mean structural relaxation time at the calorimetric glass transition temperature,respectively,have been introduced to construct the correlation with glass forming ability and thermal stability. The high value of ft for Ti41.5Cu37.5Ni7.5Zr2.5Hf5 Sn5 Si1 BMG that is higher than 0. 84 however lower than that of typical BMGs which approaches unity reveals its relatively good, however worse glass forming ability compared with typical BMGs; in addition, its high value of τ, indicates its comparable good thermal stability with typical BMGs.
Bulk metallic glass Titanium alloy Structural relaxation Glass forming ability Thermal stability
J. N. Mei J. L. Soubeyroux J. J. Blandin
State Key Laboratory of Solidification Processing, Northxvestern Polytechnical University ,Xian 710 Institut Neel/CRETA,CNRS Grenoble, 25 Avenue des Martyrs ,BP 166 ,38042 Grenoble Cedex 9 ,France SIMAP/GPM2 ,Grenoble Institut National Polytechnique ,UMR CNRS 5010 ,BP 46,38402 Saint-Martin dHere
国际会议
The 12th World Conference Titanium(第十二届世界钛会 Ti-2011)
北京
英文
1183-1186
2011-06-19（万方平台首次上网日期，不代表论文的发表时间）