Microstructural Evolution, Thermodynamics, and Kinetics of Mo-Tm2O3 Powder Mixtures during Ball MillingReportar como inadecuado


Microstructural Evolution, Thermodynamics, and Kinetics of Mo-Tm2O3 Powder Mixtures during Ball Milling


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College of Energy, Xiamen University, Xiamen 361102, China





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Academic Editor: Sergey Kustov

Abstract The microstructural evolution, thermodynamics, and kinetics of Mo 21 wt % Tm2O3 powder mixtures during ball milling were investigated using X-ray diffraction and transmission electron microscopy. Ball milling induced Tm2O3 to be decomposed and then dissolved into Mo crystal. After 96 h of ball milling, Tm2O3 was dissolved completely and the supersaturated nanocrystalline solid solution of Mo Tm, O was obtained. The Mo lattice parameter increased with increasing ball-milling time, opposite for the Mo grain size. The size and lattice parameter of Mo grains was about 8 nm and 0.31564 nm after 96 h of ball milling, respectively. Ball milling induced the elements of Mo, Tm, and O to be distributed uniformly in the ball-milled particles. Based on the semi-experimental theory of Miedema, a thermodynamic model was developed to calculate the driving force of phase evolution. There was no chemical driving force to form a crystal solid solution of Tm atoms in Mo crystal or an amorphous phase because the Gibbs free energy for both processes was higher than zero. For Mo 21 wt % Tm2O3, it was mechanical work, not the negative heat of mixing, which provided the driving force to form a supersaturated nanocrystalline Mo Tm, O solid solution. View Full-Text

Keywords: neutron absorber; Mo-based composites; ball milling; microstructure; thulium oxide neutron absorber; Mo-based composites; ball milling; microstructure; thulium oxide





Autor: Yong Luo, Guang Ran * , Nanjun Chen, Qiang Shen and Yaoli Zhang

Fuente: http://mdpi.com/



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