Content area
Eight diffusion couples were fabricated to systematically investigate the composition-dependent interdiffusion behavior in hcp Dy-Y, Dy-Nd, Sm-Nd, and Sm-Tb binary alloys. The interdiffusion coefficients were determined at two representative temperatures using the Sauer–Freise method based on concentration–distance profiles measured by electron probe microanalysis (EPMA). These experimentally obtained diffusivities, together with available thermodynamic data, were subsequently employed to assess the atomic mobilities of each system by means of the CALTPP (CALculation of Thermo Physical Properties) program within the CALPHAD (CALculation of PHAse Diagrams) framework. The optimized mobility parameters provide a reliable description of the diffusion behavior in all investigated alloys. This reliability is confirmed by the close agreement between the calculated and experimentally measured interdiffusion coefficients, as well as by the strong consistency between the model-predicted and experimental concentration profiles. The present work thus establishes the first set of critically evaluated atomic mobility parameters for these hcp rare-earth binary systems. These results fill an important gap in the kinetic database of rare-earth alloys and lay a robust foundation for future multi-component CALPHAD-based simulations, thereby supporting the design and optimization of advanced rare-earth permanent magnets with improved coercivity and thermal stability.
Details
Mathematical analysis;
Rare earth alloys;
Samarium;
Interdiffusion;
Binary systems;
Yttrium;
Electron probe microanalysis;
Temperature;
Atomic mobilities;
Binary alloys;
Dysprosium;
Phase diagrams;
Physical properties;
Hot pressing;
Terbium;
Design optimization;
Couples;
Alloys;
Parameters;
Permanent magnets;
Annealing
; Liu Qingzhu 2 ; Huang, Weiyin 3 ; Huang, Xiaozhong 1 ; Wang, Peisheng 1 ; Liu, Shuhong 4
; Du, Yong 4
1 Powder Metallurgy Research Institute, Central South University, Changsha 410083, China, Hunan Key Laboratory of Advanced Fibers and Composites, Central South University, Changsha 410083, China
2 Hunan Special Equipment Inspection and Testing Institute, Changsha 410117, China
3 School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, China
4 Powder Metallurgy Research Institute, Central South University, Changsha 410083, China